Devices, methods, and systems involving castings

ABSTRACT

Certain exemplary embodiments of the present invention comprise a device comprising a cast collimator derived from a metallic foil stack lamination mold, said collimator defining a feature adapted to contain a plurality of radiation detection elements. In certain embodiments, the collimator can define a feature adapted to contain a plurality of radiation detection elements, such as scintillators. Certain exemplary embodiments of the present invention comprise a device comprising a cast component derived from a metallic foil stack lamination mold. In various exemplary embodiments, the cast components can be a mechanical, electrical, electronic, optical, fluidic, biomedical, and/or biotechnological component. It is emphasized that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. This abstract is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 37 CFR 1.72(b).

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation-in-part of, claims priorityto, and incorporates by reference in its entirety each of:

[0002] U.S. patent application Ser. No. 10/282441, filed Oct. 29, 2002,and titled “Devices, Methods, and Systems Involving Cast ComputedTomography Collimators”;

[0003] U.S. patent application Ser. No. 10/282402, filed Oct. 29, 2002,and titled “Devices, Methods, and Systems Involving Cast Collimators”;and

[0004] PCT Patent Application Serial No. PCT/JUSO2/17936, filed Jun. 5,2002.

BRIEF DESCRIPTION OF THE DRAWINGS

[0005] The wide variety of potential embodiments of the presentinvention will be more readily understood through the following detaileddescription, with reference to the accompanying drawings in which:

[0006]FIG. 1 is a flowchart of an exemplary embodiment of a method ofthe present invention.

[0007]FIG. 2 is a flow diagram of exemplary items fabricated using amethod of the present invention.

[0008]FIG. 3 is a perspective view of an exemplary casting of thepresent invention that illustrates aspect ratio.

[0009]FIG. 4 is an assembly view of an exemplary assembly of the presentinvention.

[0010]FIG. 5A is a top view of an exemplary stack lamination mold of thepresent invention.

[0011] FIGS. 5B-5E are exemplary alternative cross-sectional views of anexemplary stack lamination mold of the present invention taken atsection lines 5-5 of FIG. 5A.

[0012]FIG. 6 is an unassembled cross-sectional view of an alternativeexemplary stack lamination mold taken of the present invention atsection lines 5-5 of FIG. 5A.

[0013]FIG. 7 is a cross-sectional view of an exemplary alternative stacklamination mold of the present invention taken at section lines 5-5 ofFIG. 5A.

[0014]FIG. 8 is a perspective view of an exemplary laminated mold.

[0015]FIG. 9 is a cross-section of an exemplary mold of the presentinvention taken along lines 9-9 of FIG. 8.

[0016]FIG. 10A is a top view an exemplary layer of the present inventionhaving a redundant array of shapes.

[0017]FIG. 10B is a top view of an exemplary layer of the presentinvention having a non-redundant collection of shapes.

[0018]FIG. 11 is a top view of an exemplary stacked lamination mold ofthe present invention.

[0019]FIG. 12 is a cross-sectional view of an exemplary mold of thepresent invention taken at section lines 12-12 of FIG. 11.

[0020]FIG. 13 is a side view of an exemplary cast part of the presentinvention formed using the exemplary mold of FIG. 11.

[0021]FIG. 14 is a top view of an exemplary laminated mold of thepresent invention.

[0022]FIG. 15 is a cross-sectional view of an exemplary mold of thepresent invention taken at section lines 15-15 of FIG. 14.

[0023]FIG. 16 is a perspective view of an exemplary cast part of thepresent invention formed using the exemplary mold of FIG. 14.

[0024]FIG. 17 is a top view of an exemplary planar laminated mold of thepresent invention having an array of openings.

[0025]FIG. 18 is a top view of an exemplary flexible casting or moldinsert of the present invention molded using the laminated mold of FIG.17.

[0026]FIG. 19 is a top view of an exemplary mold fixture of the presentinvention

[0027]FIG. 20 is a top view of an exemplary planar laminated mold of thepresent invention.

[0028]FIG. 21 is a top view of an exemplary flexible casting or moldinsert of the present invention molded using the laminated mold of FIG.20.

[0029]FIG. 22 is a top view of an exemplary mold fixture of the presentinvention

[0030]FIG. 23 is a perspective view of an exemplary laminated mold ofthe present invention.

[0031]FIG. 24 is a close-up perspective view of an exemplary singlecylindrical cavity of an exemplary mold of the present invention.

[0032]FIG. 25 is a perspective view of an exemplary cast part of thepresent invention.

[0033]FIG. 26 is a flowchart of an exemplary method of the presentinvention.

[0034]FIG. 27 is a perspective view of a plurality of exemplary layersof the present invention.

[0035]FIG. 28 is a perspective view of an exemplary laminating fixtureof the present invention.

[0036]FIG. 29 is a top view of stack lamination mold of the presentinvention that defines an array of cavities.

[0037]FIG. 30 is a cross-section of a cavity of the present inventiontaken along section lines 30-30 of FIG. 29.

[0038]FIG. 31 is a perspective view of an exemplary single corrugatedfeedhorn of the present invention.

[0039]FIG. 32 is a side view of an exemplary casting fixture of thepresent invention.

[0040]FIG. 33 is a side view of an exemplary section of cylindricaltubing of the present invention that demonstrates the shape of anexemplary fluidic channel of the present invention.

[0041]FIG. 34 is a top view of an exemplary micro-machined layer of thepresent invention.

[0042]FIG. 35 is a cross-sectional view of a laminated slit of thepresent invention taken along section lines 35-35 of FIG. 34.

[0043]FIG. 36 is a side view of a portion of an exemplary flexiblecavity insert of the present invention.

[0044]FIG. 37 is a top view of an exemplary base plate of the presentinvention.

[0045]FIG. 38 is a front view of a single exemplary flexible cavityinsert assembly of the present invention.

[0046]FIG. 39 is a front view of flexible cavity inserts of the presentinvention.

[0047]FIG. 40 is a top view of a top plate of the present invention.

[0048]FIG. 41 is a flowchart of an exemplary embodiment of a method ofthe present invention.

[0049]FIG. 42A is a top view of an exemplary laminated stack of thepresent invention.

[0050]FIG. 42B is a cross-sectional view, taken at section lines 42-42of FIG. 42A, of an exemplary laminated stack of the present invention.

[0051]FIG. 43 is side view of an exemplary mold and casting of thepresent invention.

[0052]FIG. 44 is a top view of an exemplary casting fixture of thepresent invention.

[0053]FIG. 45 is a front view of the exemplary casting fixture of FIG.44.

[0054]FIG. 46 is a top view of a portion of an exemplary grid pattern ofthe present invention.

[0055]FIG. 47 is an assembly view of components of an exemplarypixilated gamma camera of the present invention.

[0056]FIG. 48A is a top view of an array of generic microdevices of thepresent invention.

[0057]FIG. 48B is a cross-sectional view of an exemplary microdevice ofthe present invention, taken at section lines 48-48 of FIG. 48A, in theopen state.

[0058]FIG. 49 is a cross-sectional view of the exemplary microdevice ofFIG. 48B, taken at section lines 48-48 of FIG. 48A, in the closed state.

[0059]FIG. 50 is a cross-sectional view of an alternative exemplarymicrodevice of the present invention, taken at section lines 48-48 ofFIG. 48A, and shown with an inlet valve open.

[0060]FIG. 51 is a cross-sectional view of the alternative exemplarymicrodevice of FIG. 50, taken at section lines 48-48 of FIG. 48A, andshown with an outlet valve open.

[0061]FIG. 52 is a top view of an exemplary microwell array of thepresent invention.

[0062]FIG. 53 is a cross-sectional view taken at lines 52-52 of FIG. 52of an exemplary microwell of the present invention.

[0063]FIG. 54 is a cross-sectional view taken at lines 52-52 of FIG. 52of an alternative exemplary microwell of the present invention.

[0064]FIG. 55 is a top view of exemplary microwell of the presentinvention.

[0065]FIG. 56 is a cross-sectional view of an exemplary microwell of thepresent invention, taken at lines 55-55 of FIG. 55.

DETAILED DESCRIPTION

[0066] Certain exemplary embodiments of the present invention cancombine certain techniques of stack lamination with certain moldingprocesses to manufacture a final product. As a result of the stacklamination techniques, precision micro-scale cavities of predeterminedshapes can be engineered into the stack lamination. Rather than have thestack lamination embody the final product, however, the stack laminationcan be used as an intermediate in a casting or molding process.

[0067] In certain exemplary embodiments of the present invention, thestack lamination (“laminated mold”) can be made up of layers comprisingmetallic, polymeric, and/or ceramic material. The mold can be a positivereplication of a predetermined end product or a negative replicationthereof. The mold can be filled with a first cast material and allowedto solidify. A first cast product can be demolded from the mold. Thefirst cast material can comprise a flexible polymer such as siliconerubber.

[0068] Certain exemplary embodiments of a method of the presentinvention can further include surrounding the first cast product with asecond casting material and allowing the second cast material tosolidify. Still further, a second cast product can be demolded from thefirst cast product.

[0069] Some exemplary embodiments of the present invention can furtherinclude positioning an insert into the cavity prior to filling the moldwith the first cast material, wherein the insert occupies only a portionof the space defined by the cavity. The second cast product can benonplanar. The end product and/or the mold cavity can have an aspectratio greater that 100:1. The end product can be attached to thesubstrate or it can be a free-standing structure.

[0070] In certain exemplary embodiments, the master mold can befabricated using diverse micro-machining methods, which can allow hybridintegration of various disciplines. In certain exemplary embodiments,the master mold can be fabricated using high-precision lithographictechniques, which can allow production of accurate molds, castings, andfeatures having virtually any shape.

[0071] In certain exemplary embodiments, layers for master moldfabrication can be produced by using low cost materials and low costmanufacturing methods such as photo-chemical machining. In certainexemplary embodiments, the layers used for master mold fabrication canhave sub-cavities with controlled depths and shapes. These cavities canbe used to produce integrated micro-features in cast objects.

[0072] In certain exemplary embodiments, the master molds can beproduced over large areas. This allows the production of large batchesof cast micro-devices or large macro devices with incorporated arrays ofmicro features. In certain exemplary embodiments, master molds andcastings can be produced having extremely high-aspect ratios. Aspectratio's greater than 400:1 can be achieved using photo-chemicalmachining combined with precision stack lamination.

[0073] In certain exemplary embodiments, hundreds to thousands ofindividual structures can be batch produced simultaneously, eliminatingthe need to produce 3D micro-structures one at a time. In certainexemplary embodiments, many diverse materials can be used to createadvanced molds and/or cast devices. This can greatly enhance design andfabrication opportunities for low cost, application specific devices.Materials can include, but are not limited to, polymers, epoxy resins,polyesters, acrylics, ceramics, powder metals, castable metals,urethanes, silicon, and/or rubber etc. Materials can also be integratedfor production of “smart” materials needed for fabricating advanced MEMSdevices. Smart materials would include those having functionalproperties such as for example conductivity, electrostrictivity,piezoelectricity, magnetic, elastic, thermal, density, and/or chemicalresistivity, etc.

[0074] In certain exemplary embodiments, the micro devices and/orstructures can be produced as free form or attached structures. This canbe achieved through molding and casting designs or through secondarymachining techniques. In certain exemplary embodiments, micro devicescan be produced outside of clean room facilities, thereby potentiallylowering production overhead costs.

[0075] In certain exemplary embodiments, by using lithographictechniques for producing master molds and/or micro devices, arrays ofdevices or micro features can be accurately integrated and aligned withstandard microelectronics. In certain exemplary embodiments, through thefabrication method used for producing the master molds, highly accurate,three dimensional engineering and production of micro scale devices canbe possible. In certain exemplary embodiments, through the use offlexible molds, highly accurate, three dimensional engineering andproduction of non-planar, micro scale devices is possible. Non-planarshapes can include, but are not limited to, curves, arcs, diameters,spherical radii, inside and outside diameters of cylinders, etc.

[0076]FIG. 1 is a flowchart of an exemplary embodiment of a method 1000of the present invention. At activity 1010, a mold design is determined.At activity 1020, the layers of the mold (“laminations”) are fabricated.At activity 1030, the laminations are stacked and assembled into a mold(a derived mold could be produced at this point as shown in FIG. 1). Atactivity 1060, a first casting is cast. At activity 1070, the firstcasting is demolded.

[0077]FIG. 2 is a flow diagram of exemplary items fabricated during amethod 2000 of the present invention. Layers 2010 can be stacked to forma mold or stacked lamination 2020. A molding or casting material can beapplied to mold 2020 to create a molding or casting 2030, that can bedemolded from mold 2020.

[0078]FIG. 3 is a perspective view of an exemplary molding 3000 of thepresent invention that demonstrates a parameter referred to herein as“aspect ratio” which is described below. Molded block 3010 has numerousthrough-holes 3020, each having a height H and a diameter or width W.For the purposes of this application, aspect ratio is defined as theratio of height to width or H/W of a feature, and can apply to any“negative” structural feature, such as a space, channel, through-hole,cavity, etc., and can apply to a “positive” feature, such as a wall,projection, protrusion, etc., with the height of the feature measuredalong the Z-axis. Note that all features can be “bordered” by at leastone “wall”. For a positive feature, the wall is part of the feature. Fora negative feature, the wall at least partially defines the feature.

[0079]FIG. 3 also demonstrates the X-, Y-, and Z-directions or axes. Forthe purposes of this application, the dimensions measured in the X- andY-directions define a top surface of a structure (such as a layer, astack lamination mold, or negative and/or positive replications thereof)when viewed from the top of the structure. The Z-direction is the thirddimension perpendicular to the X-Y plane, and corresponds to the line ofsight when viewing a point on a top surface of a structure from directlyabove that point.

[0080] Certain embodiments of a method of the present invention cancontrol aspect ratios for some or all features in a laminated mold,derived mold, and/or cast item (casting). The ability to attainrelatively high aspect ratios can be affected by a feature's geometricshape, size, material, and/or proximity to another feature. This abilitycan be enhanced using certain embodiments of the present invention. Forexample, through-features of a mold, derived mold, and/or final part,having a width or diameter of approximately 5 microns, can have adimension along the Z axis (height) of approximately 100 microns, orapproximately 500 microns, or any value in the range there between(implying an aspect ratio of approximately 20:1, 100:1, or any value inthe range therebetween, including, for example:

[0081] 20:1 to 30:1, 20:1 to 40:1, 20:1 to 50:1, 20:1 to 60:1, 20:1 to70:1, 20:1 to 80:1, 20:1 to 90:1, 20:1 to 100:1,

[0082]30:1 to 40:1, 30:1 to 50:1, 30:1 to 60:1, 30:1 to 70:1, 30:1 to80:1, 30:1 to 90:1, 30:1 to 100:1,

[0083]40:1 to 50:1, 40:1 to 60:1, 40:1 to 70:1, 40:1 to 80:1, 40:1 to90:1, 40:1 to 100:1,

[0084]50:1 to 60:1, 50:1 to 70:1, 50:1 to 80:1, 50:1 to 90:1, 50:1 to100:1,

[0085]60:1 to 70:1, 60:1 to 80:1, 60:1 to 90:1, 60:1 to 100:1,

[0086]70:1 to 80:1, 70:1 to 90:1, 70:1 to 100:1,

[0087]80:1 to 90:1, 80:1 to 100:1, etc).

[0088] As another example, a through slit having a width ofapproximately 20 microns can have a height of approximately 800 microns,or approximately 1600 microns, or any value in the range therebetween(implying an aspect ratio of approximately 40:1, 80:1, or any value inthe range therebetween, including, for example:

[0089] 40:1 to 50:1, 40:1 to 60:1, 40:1 to 70:1, 40:1 to 80:1,

[0090] 50:1 to 60:1, 50:1 to 70:1, 50:1 to 80:1,

[0091] 60:1 to 70:1, 60:1 to 80:1,

[0092] 70:1 to 80:1, etc).

[0093] As yet another example, the same approximately 20 micron slit canbe separated by an approximately 15 micron wide wall in an array, wherethe wall can have a dimension along the Z axis (height) of approximately800 microns, or approximately 1600 microns, or any value in the rangetherebetween (implying an aspect ratio of approximately 53:1, 114:1, orany value in the range therebetween, including, for example:

[0094] 53:1 to 60:1, 53:1 to 70:1, 53:1 to 80:1, 53:1 to 90:1, 53:1 to100:1, 53:1 to 110:1, 53:1 to 114:1,

[0095] 60:1 to 70:1, 60:1 to 80:1, 60:1 to 90:1, 60:1 to 100:1, 60:1 to110:1, 60:1 to 114:1,

[0096] 70:1 to 80:1, 70:1 to 90:1, 70:1 to 100:1, 70:1 to 110:1, 70:1 to114:1,

[0097] 80:1 to 90:1, 80:1 to 100:1, 90:1 to 110:1, 90:1 to 114:1,

[0098]90:1 to 100:1, 90:1 to 110:1, 90:1 to 114:1,

[0099] 100:1 to 110:1, 100:1 to 114:1, etc.).

[0100] Still another example is an array of square-shaped openingshaving sides that are approximately 0.850 millimeters wide, each openingseparated by approximately 0.150 millimeter walls, with a dimensionalong the Z axis of approximately 30 centimeters. In this example theapproximately 0.850 square openings have an aspect ratio ofapproximately 353:1, and the approximately 0.150 walls have an aspectratio of approximately 2000:1, with lesser aspect ratios possible. Thus,the aspect ratio of the openings can be approximately 10:1, orapproximately 350:1, or any value in the range therebetween, includingfor example:

[0101] 10:1 to 20:1, 10:1 to 30:1, 10:1 to 40:1, 10:1 to 50:1, 10:1 to60:1, 10:1 to 70:1, 10:1 to 80:1, 10:1 to 90:1, 10:1 to 100:1, 10:1 to150:1, 10:1 to 200:1, 10:1 to 250:1, 10:1 to 300:1, 10:1 to 350:1, 20:1to 30:1, 20:1 to 40:1, 20:1 to 50:1, 20:1 to 60:1, 20:1 to 70:1, 20:1 to80:1,

[0102] 20:1 to 90:1, 20:1 to 100:1, 20:1 to 150:1, 20:1 to 200:1, 20:1to 250:1, 20:1 to 300:1, 20:1 to 350:1,

[0103] 30:1 to 40:1, 30:1 to 50:1, 30:1 to 60:1, 30:1 to 70:1, 30:1 to80:1, 30:1 to 90:1, 30:1 to 100:1, 30:1 to 150:1, 30:1 to 200:1, 30:1 to250:1, 30:1 to 300:1, 30:1 to 350:1,

[0104] 40:1 to 50:1, 40:1 to 60:1, 40:1 to 70:1, 40:1 to 80:1, 40:1 to90:1, 40:1 to 100:1, 40:1 to 150:1, 40:1 to 200:1, 40:1 to 250:1, 40:1to 300:1, 40:1 to 350:1,

[0105] 50:1 to 60:1, 50:1 to 70:1, 50:1 to 80:1, 50:1 to 90:1, 50:1 to100:1, 50:1 to 150:1, 50:1 to 200:1, 50:1 to 250:1, 50:1 to 300:1, 50:1to 350:1,

[0106] 75:1 to 80:1, 75:1 to 90:1, 75:1 to 100:1, 75:1 to 150:1, 75:1 to200:1, 75:1 to 250:1, 75:1 to 300:1, 75:1 to 350:1,

[0107] 100:1 to 150:1, 100:1 to 200:1, 100:1 to 250:1, 100:1 to 300:1,100:1 to 350:1,

[0108] 150:1 to 200:1, 150:1 to 250:1, 150:1 to 300:1, 150:1 to 350:1,

[0109] 200:1 to 250:1, 200:1 to 300:1, 200:1 to 350:1,

[0110] 250:1 to 300:1, 250:1 to 350:1,

[0111] 300:1 to 350:1, etc.

[0112] Moreover, the aspect ratio of the walls can be approximately10:1, or approximately 2000:1, or any value in the range therebetween,including for example:

[0113] 10:1 to 20:1, 10:1 to 30:1, 10:1 to 40:1, 10:1 to 50:1, 10:1 to100:1, 10:1 to 200:1, 10:1 to 500:1, 10:1 to 1000:1, 10:1 to 2000:1,

[0114] 20:1 to 30:1, 20:1 to 40:1, 20:1 to 50:1, 20:1 to 100:1, 20:1 to200:1, 20:1 to 500:1, 20:1 to 1000:1, 20:1 to 2000:1,

[0115] 30:1 to 40:1, 30:1 to 50:1, 30:1 to 100:1, 30:1 to 200:1, 30:1 to500:1, 30:1 to 1000:1, 30:1 to 2000:1,

[0116] 40:1 to 50:1, 40:1 to 100:1, 40:1 to 200:1, 40:1 to 500:1, 40:1to 1000:1, 40:1 to 2000:1,

[0117] 50:1 to 100:1, 50:1 to 200:1, 50:1 to 500:1, 50:1 to 1000:1, 50:1to 2000:1,

[0118] 100:1 to 200:1, 100:1 to 500:1, 100:1 to 1000:1, 100:1 to 2000:1,

[0119] 200:1 to 500:1, 200:1 to 1000:1, 200:1 to 2000:1,

[0120] 500:1 to 1000:1, 500:1 to 2000:1,

[0121] 1000:1 to 2000:1, etc.

[0122] Another example of aspect ratio is the space between solid(positive) features of a mold, derived mold, and/or casting. Forexample, as viewed from the top, a casting can have two or more solidrectangles measuring approximately 50 microns wide by approximately 100microns deep with an approximately 5 micron space therebetween (eitherwidth-wise or depth-wise). The rectangles can have a height of 100microns, or 500 microns, or any value in the range therebetween(implying an aspect ratio of 20:1, or 100:1, or any value therebetween,including, for example:

[0123] 20:1 to 30:1, 20:1 to 40:1, 20:1 to 50:1, 20:1 to 60:1, 20:1 to70:1, 20:1 to 80:1, 20:1 to 90:1, 20:1 to 100:1,

[0124] 30:1 to 40:1, 30:1 to 50:1, 30:1 to 60:1, 30:1 to 70:1, 30:1 to80:1, 30:1 to 90:1, 30:1 to 100:1,

[0125] 40:1 to 50:1, 40:1 to 60:1, 40:1 to 70:1, 40:1 to 80:1, 40:1 to90:1, 40:1 to 100:1,

[0126] 50:1 to 60:1, 50:1 to 70:1, 50:1 to 80:1, 50:1 to 90:1, 50:1 to100:1,

[0127] 60:1 to 70:1, 60:1 to 80:1, 60:1 to 90:1, 60:1 to 100:1,

[0128] 70:1 to 80:1, 70:1 to 90:1, 70:1 to 100:1,

[0129] 80:1 to 90:1, 80:1 to 100:1, etc).

[0130] In another example the same rectangles can have a space therebetween of approximately 20 microns, and the rectangles can havedimensions along the Z axis of approximately 800 microns, orapproximately 5000 microns, or any value therebetween (implying anaspect ratio of approximately 40:1, or 250:1, or any value therebetween,including, for example:

[0131] 40:1 to 50:1, 40:1 to 75:1, 40:1 to 100:1, 40:1 to 150:1, 40:1 to200:1, 40:1 to 250:1,

[0132] 75:1 to 100:1, 75:1 to 150:1, 75:1 to 200:1, 75:1 to 250:1,

[0133] 100:1 to 150:1, 100:1 to 200:1, 100:1 to 250:1,

[0134] 150:1 to 200:1, 150:1 to 250:1,

[0135]200:1 to 250:1, etc).

[0136]FIG. 4 is an assembly view of an exemplary assembly 4000 of thepresent invention that includes mold 4010 and cast part 4020 formed frommold 4010. Because certain exemplary embodiments of the presentinvention can utilize lithographically-derived micro-machiningtechniques (or in some cases, non-lithographically-derivedmicro-machining techniques, such as laser machining) combined withmolding and/or casting, laminated molds can be conceived as negatives4010 or positives 4020 of the desired end product. The terms “negative”or “positive” replications can be subjective terms assigned to differentstages of reaching an end product. For certain embodiments, anyintermediate or the end product can be considered a negative or positivereplication depending on a subject's point of view. For the purpose ofthis application, a “positive” replication is an object (whether anintermediate or an end product) that geometrically resembles at least aportion of the spatial form of the end product. Conversely, a “negative”replication is a mold that geometrically defines at least a portion ofthe spatial form of the end product. The following parameters aredescribed for the purpose of demonstrating some of the potential designparameters of certain embodiments of a method of the present invention.

[0137] Layer Thickness

[0138] One design parameter can be the thickness of the micro-machinedlayers of the stack lamination mold. According to certain exemplaryembodiments of the present invention, to achieve high-aspect ratios,multiple micro-machined foils or layers can be stacked in succession andbonded together. In certain exemplary embodiments of the presentinvention, the layer thickness can have a dimensional role in creatingthe desired shape in the third dimension. FIG. 5A is a top view of anexemplary stack lamination mold 5000. FIGS. 5B-5E are exemplaryalternative cross-sectional views of exemplary stack lamination mold5000 taken at section lines 5-5 of FIG. 5A. As shown in FIG. 5B and FIG.5D, respectively, stacks 5010 and 5020 utilize relatively thick layers.As shown in FIG. 5C and FIG. 5E, respectively, stacks 5030 and 5040utilize relatively thinner layers in succession to smooth out resolutionalong the z-axis. Specific layers can have multiple functions that canbe achieved through their thickness or other incorporated featuresdescribed herein.

[0139] Cross-Sectional Shape of Layer

[0140] One design parameter can be the cross sectional shape of a givenlayer in the mold. Through the use of etching and/or depositiontechniques, many cross sectional shapes can be obtained. FIG. 6 is anunassembled cross-sectional view of an alternative exemplary stacklamination mold 5000 taken at section lines 5-5 of FIG. 5A. Each ofexemplary layers 6010, 6020, 6030, and 6040 of FIG. 6 define anexemplary through-feature 6012, 6022, 6032, 6042, respectively, eachhaving a different shape, orientation, and/or configuration. Thesethrough-features 6012, 6022, 6032, 6042 are bordered by one or more“sidewalls” 6014, 6024, 6034, and 6044, respectively, as they arecommonly referred to in the field of lithographic micro-machining.

[0141] Etching disciplines that can be utilized for a layer of the moldcan be broadly categorized as isotropic (non-linear) or anisotropic(linear), depending on the shape of the remaining sidewalls. Isotropicoften refers to those techniques that produce one or more radial or hourglassed shaped sidewalls, such as those shown in layer 6010. Anisotropictechniques produce one or more sidewalls that are more verticallystraight, such as those shown in layer 6020.

[0142] Additionally, the shape of a feature that can be etched through afoil of the mold can be controlled by the depth of etching on eachsurface and/or the configuration of the photo-mask. In the case ofphoto-chemical-machining, a term such as 90/10 etching is typically usedto describe the practice of etching 90% through the foil thickness, fromone side of the foil, and finishing the etching through the remaining10% from the other side, such as shown on layer 6030. Other etch ratioscan be obtained, such as 80/20, 70/30, and/or 65/35, etc., for variousfoils and/or various features on a given foil.

[0143] Also, the practice of displacing the positional alignment offeatures from the top mask to the bottom mask can be used to alter thesidewall conditions for a layer of the mold, such as shown in layer6040.

[0144] By using these and/or other specific conditions as designparameters, layers can be placed to contribute to the net shape of the3-dimensional structure, and/or provide specific function to that regionof the device. For example, an hourglass sidewall could be used as afluid channel and/or to provide structural features to the device. FIG.7 is a cross-sectional view of an alternative exemplary stack laminationmold taken at section line 5-5 of FIG. 5A. FIG. 7 shows a laminated mold5000 having layers 7010, 7020, 7030, 7040 that define cavity 7060. Toachieve this, layers 7010, 7020 are etched anisotropically to havestraight sidewalls, while layer 7030 is thicker than the other layersand is etched isotropically to form the complex shaped cross-sectionshown.

[0145] Cross-Sectional Surface Condition of Layer

[0146] Another design parameter when creating advanced three-dimensionalstructures can be the cross-sectional surface condition of the layersused to create a laminated mold. As is the case with sidewall shape,surface condition can be used to provide additional function to astructure or a particular region of the structure. FIG. 8 is aperspective view of a generic laminated mold 8000. FIG. 9 is across-section of mold 8000 taken at lines 9-9 of FIG. 8. Any sidewallsurface, top or bottom surface can be created with one or more specificfinish conditions on all layers or on selected layers, such as forexample, forming a relatively rough surface on at least a portion of asidewall 9100 of certain through-features 9200 of layer 9300. As anotherexample, chemical and/or ion etching can be used to produce very smooth,polished surfaces through the use of selected materials and/orprocessing techniques. Similarly, these etching methods can also bemanipulated to produce very rough surfaces.

[0147] Secondary techniques, such as electro-plating and/or passivechemical treatments can also be applied to micromachined surfaces (suchas a layer of the mold) to alter the finish. Certain secondarytechniques (for example, lapping or superfinishing) can also be appliedto non-micromachined surfaces, such as the top or bottom surfaces of alayer. In any event, using standard profile measuring techniques,described as “roughness average” (R_(a)) or “arithmetic average” (AA),the following approximate ranges for surface finish (or surfaceconditions) are attainable using micromachining and/or one or moresecondary techniques according to certain embodiments of the presentinvention (units in microns):

[0148] 50 to any of: 25, 12.5, 6.3, 3.2, 1.6, 0.80, 0.40, 0.20, 0.10,0.050, 0.025,

[0149] 25 to any of: 12.5, 6.3, 3.2, 1.6, 0.80, 0.40, 0.20, 0.10, 0.050,0.025,

[0150] 12.5 to any of: 6.3, 3.2, 1.6, 0.80, 0.40, 0.20, 0.10, 0.050,0.025,

[0151] 6.3 to any of: 3.2, 1.6, 0.80, 0.40, 0.20, 0.10, 0.050, 0.025,

[0152] 3.2 to any of: 1.6, 0.80, 0.40, 0.20, 0.10, 0.050, 0.025,

[0153] 1.6 to any of: 0.80, 0.40, 0.20, 0.10, 0.050, 0.025,

[0154] 0.80 to any of: 0.40, 0.20, 0.10, 0.050, 0.025,

[0155] 0.40 to any of: 0.20, 0.10, 0.050, 0.025,

[0156] 0.20 to any of: 0.10, 0.050, 0.025,

[0157] 0.10 to any of: 0.050, 0.025,

[0158] 0.050 to any of: 0.025, etc.

[0159] Additional Layer Features

[0160] Certain exemplary embodiments of the present invention caninclude layer features that can be created through the use oflithographic etching and/or deposition. These embodiments can includethe size, shape, and/or positional orientation of features relative tothe X- and/or Y-axes of a layer and/or their relationship to features onneighboring layers along the Z-axis of the assembled laminated mold.These parameters can define certain geometric aspects of the structure.For example, FIG. 10A is a top view of a layer 10010 having a pattern ofrepeating features (a redundant array of shapes), and FIG. 10B is a topview of a layer 10020 having a variety of differently shaped features (anon-redundant collection of shapes). Although not shown, a layer canhave both redundant and non-redundant features. The terms “redundant”and/or “non-redundant” can refer to either positive or negativefeatures.

[0161] Thus, these parameters also can define the shapes and/or spatialforms of features, the number of features in a given area, secondarystructures and/or spaces incorporated on or around a feature, and/or thespaces between features. The control of spacing between features canprovide additional functionality and, for instance, allow integration ofdevices with micro-electronics. For example, conductive micro featurescould be arrayed (redundantly or non-redundantly) to align accuratelywith application specific integrated circuits (ASIC) to controlfeatures. Also, features could be arrayed for applications wherenon-linear spacing between features could enhance device functionality.For example, filtration elements could be arrayed in such a way as tomatch the flow and pressure profile of a fluid passing over or through afiltration media. The spacing of the filtration elements could bearrayed to compensate for the non-linear movement of the fluid.

[0162] Cavity Definition Using Lithography

[0163] A cavity formed in accordance with certain exemplary embodimentsof the present invention can assume a shape and/or spatial form thatincludes one or more predetermined “protruding undercuts”. Imaginablyrotating the X-Y plane about its origin to any particular fixedorientation, a cavity is defined as having a “protruding undercut” whena first section of the cavity taken perpendicular to the Z-axis (i.e.,parallel to the X-Y plane) has a predetermined dimension in the X-and/or Y-direction greater than the corresponding dimension in the X-and/or Y-direction of a second section of the cavity taken perpendicularto the Z-axis, the second section further along in the direction ofeventual demolding of a cast part relative to the mold (assuming thedemolding operation involves pulling the cast part free from the mold).That is, the X-dimension of the first section is intentionally greaterthan the X-dimension of the second section by a predetermined amount, orthe Y-dimension of the first section is intentionally greater than theY-dimension of the second section by a predetermined amount, or both. Instill other words, for the purposes of this patent application, the termprotruding undercut has a directional component to its definition.

[0164]FIG. 11 is a top view of an exemplary stacked laminated mold11000. FIG. 12 is a cross-sectional view of a mold 11000 taken atsection lines 12-12 of FIG. 11, and showing the layers 12010-12060 ofmold 11000 that cooperatively define a cavity having protrudingundercuts 12022 and 12042. Direction A is the relative direction inwhich a part cast using mold 11000 will be demolded, and/or pulled away,from mold 11000. FIG. 12 also shows that certain layers 12020, 12040 ofmold 12000 have been formed by controlled depth etching. FIG. 13 is aside view of a cast part 13000 formed using mold 111000.

[0165] To make layers for certain embodiments of a laminated mold of thepresent invention, such as layers 2010 of FIG. 2, a photo-sensitiveresist material coating (not shown) can be applied to one or more of themajor surfaces (i.e., either of the relatively large planar “top” or“bottom” surfaces) of a micro-machining blank. After the blank has beenprovided with a photo-resist material coating on its surfaces, “masktools” or “negatives” or “negative masks”, containing a negative imageof the desired pattern of openings and registration features to beetched in the blank, can be applied in alignment with each other and inintimate contact with the surfaces of the blank (photo-resist materialsare also available for positive patterns). The mask tools or negativescan be made from glass, which has a relatively low thermal expansioncoefficient. Materials other than glass can be used provided that suchmaterials transmit radiation such as ultraviolet light and have areasonably low coefficient of thermal expansion, or are utilized in acarefully thermally-controlled environment. The mask tools can beconfigured to provide an opening of any desired shape and furtherconfigured to provide substantially any desired pattern of openings.

[0166] The resulting sandwich of two negative masks aligned inregistration and flanking both surfaces of the blank then can be exposedto radiation, typically in the form of ultraviolet light projected onboth surfaces through the negative masks, to expose the photo-resistcoatings to the radiation. Typically, the photo-resist that is exposedto the ultraviolet light is sensitized while the photo-resist that isnot exposed is not sensitized because the light is blocked by eachnegative masks' features. The negative masks then can be removed and adeveloper solution can be applied to the surfaces of the blank todevelop the exposed (sensitized) photo-resist material.

[0167] Once the photo-resist is developed, the blanks can bemicro-machined using one or more of the techniques described herein. Forexample, when using photo-chemical-machining, an etching solution canreact with and remove the layer material not covered by the photo-resistto form the precision openings in the layer. Once etching or machiningis complete, the remaining unsensitized photo-resist can be removedusing a chemical stripping solution.

[0168] Sub-Cavities on Layers

[0169] Cavities can include sub-cavities, which can be engineered andincorporated into the molding and casting scheme using several methods.FIG. 14 is a top view of a laminated mold 14000. FIG. 15 is across-sectional view of mold 14000 taken at section lines 15-15 of FIG.14, and showing the sub-cavities 15010 within layer 15030 of mold 14000.Note that because layer 15030 is sandwiched between layers 15020 and15040, sub-cavities 15010 can be considered “sandwiched”, becausesub-cavities are at least partially bounded by a ceiling layer (e.g.,15020) and a floor layer (e.g., 15040). Note that, although not shown, asub-cavity can extend to one or more outer edges of its layer, therebyforming, for example, a sandwiched channel, vent, sprew, etc. FIG. 16 isa perspective view of cast part 16000 formed using mold 14000, andhaving protrusions 16010 that reflectively (invertedly) replicatesandwiched sub-cavities 15010.

[0170] Because cast part can very accurately reflect the geometries ofsub-cavities, such sub-cavities can be used to produce secondaryfeatures that can be incorporated with a desired structure. Examples ofsecondary features include fluid channels passing through or betweenfeatures, protrusions such as fixation members (similar to Velcro-typehooks), reservoirs, and/or abrasive surfaces. Moreover, a secondaryfeature can have a wall which can have predetermined surface finish, asdescribed herein.

[0171] There are a number of methods for producing sub-cavities in alaminated. For example, in the field of photo-chemical-machining, thepractice of partially etching features to a specified depth is commonlyreferred to as “controlled depth etching” or CDE. CDE features can beincorporated around the periphery of an etched feature, such as athrough-diameter. Because the CDE feature is partially etched on, forexample, the top surface of the layer, it can become a closed cavitywhen an additional layer is placed on top.

[0172] Another method could be to fully etch the sub-cavity featurethrough the thickness of the layer. A cavity then can be created whenthe etched-through feature is sandwiched between layers without thefeatures, such as is shown in FIG. 15.

[0173] Combinations of micro-machining techniques can be used to createsub-cavities. For example, photo-chemical-machining (PCM) can be used tocreate the etched-through feature in the layer, while ion etching couldbe applied as a secondary process to produce the sub-cavities. Bycombined etching techniques, the sub-cavities can be etched with muchfiner detail than that of PCM.

[0174] Micro-Structures, Features, and Arrays on Non-Planar Surfaces

[0175] Certain exemplary embodiments of the present invention can allowthe production of complex three-dimensional micro-devices on contouredsurfaces through the use of a flexible cavity mold insert.

[0176] One activity of such a process can be the creation of a planarlaminated mold (stack lamination), which can define the surface or3-dimensional structures. A second mold (derived mold) can be producedfrom the lamination using a flexible molding material such as siliconeRTV. The derived mold can be produced having a thin backing or membranelayer, which can act as a substrate for the 3-dimensional surface orfeatures. The membrane then can be mechanically attached to thecontoured surface of a mold insert, which can define the casting's finalshape with the incorporated 3-dimensional features or surface.

[0177] Because a mold can be derived from a series of previous molds,any derived mold can be considered to be descended from each mold inthat series. Thus, a given derived mold can have a “parent” mold, andpotentially a “grandparent” mold, etc. Likewise, from a stack laminationcan descend a first derived, descendant, or child mold, from which asecond derived, descendent, or grandchild mold can be descended, and soforth. Thus, as used herein to describe the relationship between moldsand castings, the root verbs “derive” and “descend” are considered to besynonymous.

[0178] As an example, FIG. 17 is a top view of a planar laminated mold17010 having an array of openings 17020. FIG. 18 is a top view of aflexible casting or mold insert 18010 molded using laminated mold 17010.Flexible mold insert 18010 has an array of appendages 18020corresponding to the array of openings 17020, and a backing layer 18030of a controlled predetermined thickness.

[0179]FIG. 19 is a top view of a mold fixture 19010 having an outerdiameter 19020 and an inner diameter 19030. Placed around a cylinder ormandrel 19040 within mold fixture 19010 is flexible mold insert 18010,defining a pour region 19050.

[0180] Upon filling pour region 19050, a casting is formed that definesa cylindrical tube having a pattern of cavities accessible from itsinner diameter and corresponding to and formed by the array ofappendages 18020 of flexible mold insert 18010.

[0181] As another example, FIG. 20 is a top view of a planar laminatedmold 20010 having an array of openings 20020. FIG. 21 is a top view of aflexible casting or mold insert 21010 molded using laminated mold 20010.Flexible mold insert 21010 has an array of appendages 21020corresponding to the array of openings 20020, and a backing layer 21030of a controlled predetermined thickness.

[0182]FIG. 22 is a top view of a mold fixture 22010 having an outerdiameter 22020 and an inner diameter 22030. Placed around the insidediameter 22030 within mold fixture 22010 is flexible mold insert 21010,defining a pour region 22050.

[0183] Upon filling pour region 22050, a casting is formed that definesa cylindrical tube having a pattern of cavities accessible from itsouter diameter and corresponding to and formed by the array ofappendages 21020 of flexible mold insert 21010.

[0184] Through these and related approaches, the 3-dimensional structureor surface can be built-up at the planar stage, and can be compensatedfor any distortions caused by forming the membrane to the contouredsurface. The fabrication of the laminated mold can use specific orcombined micro-machining techniques for producing the layers that definethe aspect-ratio and 3-dimensional geometry. Micro-surfaces and/orstructures can be transferred to many contours and/or shapes. Forexample, micro-patterns can be transferred to the inside and/or outsidediameter of cylinders or tubes. Specific examples demonstrating thecapabilities of this method are provided later in this document.

[0185] Cavity Inserts

[0186] The term mold insert is used herein to describe a micro-machinedpattern that is used for molding and/or fabrication of a castmicro-device, part, and/or item. The laminated or derived mold describedin this document also can be considered a mold insert. Cavity insertsare described here as a subset of a mold insert. Cavity inserts areobjects and/or assemblies that can be placed within a cavity section ofa mold but that do not take up the entire cavity space, and that providefurther features to a 3-dimensional mold.

[0187] As an example, FIG. 23 is a perspective view of a laminated mold23010 having an array of cylindrical cavities 23020, each extending fromtop to bottom of mold 23010. FIG. 24 is a close-up perspective view of asingle cylindrical cavity 23020 of mold 23010. Suspended and extendingwithin cavity 23020 are a number of cavity inserts 23030. FIG. 25 is aperspective view of a cast part 25010 having numerous cavities 25020formed by cavity inserts 23030.

[0188] A cavity insert can also be produced using certain embodiments ofthe present invention. This is further explained later in the section onnon-planar molds. An insert can be a portion of a mold in the sense thatthe insert will be removed from the cast product to leave a space havinga predetermined shape within the product. An insert alternatively canbecome part of a final molded product. For instance, if it is desirableto have a composite end product, then a process can be engineered toleave an insert in place in the final molded product.

[0189] As an example of a cavity insert, a 3-dimensional mold insert canbe produced using one or more embodiments of the present invention, theinsert having an array of cavities that are through-diameters. The castpart derived from this mold can reverse the cavities of the mold assolid diameters having the shape, size and height defined by the mold.To further enhance functionality, cavity inserts can be added to themold before the final casting is produced. In this case, the cavityinsert can be a wire formed in the shape of a spring. The spring canhave the physical dimensions required to fit within a cavity opening ofthe mold, and can be held in position with a secondary fixture scheme.The spring-shaped cavity insert can be removed from the cast part afterthe final casting process is completed. Thus, the cavity section of themold can define the solid shape of the casting while the cavity insertcan form a channel through the solid body in the shape and width of theinsert (the spring). The cavity can serve as, for example, a reservoirand/or a fluid flow restrictor.

[0190] The examples given above demonstrate the basic principle of acavity insert. Additional design and fabrication advances can berealized by using this method to create cavity inserts. For example,photo-chemical-machining can be used to create a mold that has largercavity openings, while reactive-ion-etching can be used to create finerfeatures on a cavity insert.

[0191] Fabricating the Laminated Mold

[0192] Certain exemplary embodiments of the present invention caninvolve the fabrication of a laminated mold which is used directlyand/or as an intermediate mold in one or more subsequent casting and/ormolding processes.

[0193]FIG. 26 is a block diagram illustrating various devices formedduring an exemplary method 26000 for fabricating a laminated mold havingmicro-machined layers that can be patterned and/or etched, and stackedto create a 3-dimensional mold. The laminated mold can be produced as anegative or positive replication of the desired finished casting. Forthe purpose of creating a laminated mold, any of three elements can beimplemented:

[0194] 1) creating a lithographic mask 26010 defining the features ofeach unique layer,

[0195] 2) using lithographic micro-machining techniques and/ormicro-machining techniques to produce patterned layers 26020, and/or

[0196] 3) aligning, stacking, and/or laminating the patterned layersinto a stack 26030 in order to achieve the desired 3-dimensional cavityshape, aspect ratios, and/or mold parameters desired for a laminatedmold 26040.

[0197] Lithographic Techniques

[0198] Using lithography as a basis for layer fabrication, parts and/orfeatures can be designed as diameters, squares, rectangles, hexagons,and/or any other shape and/or combination of shapes. The combinations ofany number of shapes can result in non-redundant design arrays (i.e.patterns in which not all shapes, sizes, and/or spacings are identical,as shown in FIG. 10). Lithographic features can represent solid orthrough aspects of the final part. Such feature designs can be usefulfor fabricating micro-structures, surfaces, and/or any other structurethat can employ a redundant and/or non-redundant design for certainmicro-structural aspects. Large area, dense arrays can be producedthrough the lithographic process, thereby enabling creation of deviceswith sub-features and/or the repeatable production of multiple devicesin a batch format. Note that such repeatable batch production can occurwithout substantial degradation of the mold.

[0199] Lithography can also allow the creation of very accurate featuretolerances since those features can be derived from a potentiallyhigh-resolution photographic mask. The tolerance accuracy can includeline-width resolution and/or positional accuracy of the plotted featuresover the desired area. In certain embodiments, such tolerance accuracycan enable micro-scale fabrication and/or accurate integration ofcreated micro-mechanical devices with microelectronics.

[0200] Photographic masks can assist with achieving high accuracy whenchemical or ion-etched, or deposition-processed layers are being used toform a laminated mold through stack lamination. Because dimensionalchanges can occur during the final casting process in a mold,compensation factors can be engineered at the photo-mask stage, whichcan be transferred into the mold design and fabrication. Thesecompensation factors can help achieve needed accuracy and predictabilitythroughout the molding and casting process.

[0201] Photographic masks can have a wide range of potential featuresizes and positional accuracies. For example, when using an IGIMaskwrite 800 photoplotter, an active plotting area of 22.8×31.5 inches,minimum feature size of 5 microns, and positional accuracy of +−1 micronwithin a 15×15 inch area is possible. Using higher resolutionlithographic systems for mask generation, such as those employed forelectron beam lithography, feature sizes as small as 0.25 microns areachievable, with positional tolerances similar to the Maskwrite plotter,within an area of 6×6 inches.

[0202] Layer Machining and Material Options

[0203] Another aspect to fabricating the laminated mold can be theparticular technique or techniques used to machine or mill-out thefeatures or patterns from the layer material. In certain embodiments,combining lithographic imaging and micro-machining techniques canimprove the design and fabrication of high-aspect-ratio, 3-dimensionalstructures. Some of the micro machining techniques that can be used tofabricate layers for a laminated mold include photo-etching, lasermachining, reactive ion etching, electroplating, vapor deposition, bulkmicro-machining, surface micro-machining, and/or conventional machining.

[0204] In certain exemplary embodiments, a laminated mold need onlyembody the mechanical features (e.g., size, shape, thickness, etc.) ofthe final casting. That is, it does not have to embody the specificfunctional properties (i.e. density, conductivity) that are desired tofulfill the application of the final casting. This means that anysuitable techniques or materials can be used to produce the layers ofthe mold.

[0205] Thus, there can be a wide variety of material and fabricationoptions, which can allow for a wide variety of engineered features of alayer, laminated mold, and/or derived mold. For instance, althoughphoto-chemical machining can be limited to metallic foils, by usinglaser machining or reactive ion etching, the choice of materials canbecome greatly expanded. With regard to laser machining, Resonetics,Inc. of Nashua, N.H. commercially provides laser machining services andsystems. For laser machining, a very wide range of materials can beprocessed using UV and infra-red laser sources. These materials includeceramics, metals, plastics, polymers, and/or inorganics. Lasermicro-machining processes also can extend the limits of chemicalmachining with regards to feature size and/or accuracy. With little orno restriction on feature geometry, sizes on the order of 2 microns canbe achievable using laser machining.

[0206] When a wide variety of materials are available for making thelaminated mold, process-compatibility issues can be resolved whenchoosing the material from which to create the mold. An example of thiswould be to match the thermal properties of casting materials with thoseof the laminated mold, in instances where elevated temperatures areneeded in the casting or molding process. Also the de-molding propertiesof the mold and/or casting material can be relevant to the survival ofthe mold. This, for example, might lead one to laser-machine the layersfrom a material such as Teflon, instead of a metal. The laser machiningprocess could be compatible with the Teflon and the Teflon could havegreater de-molding capabilities than a metallic stack lamination.

[0207] In certain exemplary embodiments of the present invention, only asingle laminated stack is needed to produce molds or castings. Also, incertain exemplary embodiments of the present invention, molds and/orcastings can be produced without the need for a clean-room processingenvironment.

[0208] For certain exemplary embodiments of the present invention, theability to create a single laminated mold and then cast the final partscan allow for using much thinner foils or advanced etching methods forproducing the individual layers. Since feature size can be limited bythe thickness of each foil, using thinner foils can allow finer featuresto be etched.

[0209] Certain exemplary embodiments of the present invention cancombine various micro-machining techniques to create layers that havevery specific functional features that can be placed in predeterminedlocations along the Z-axis of the mold assembly. For example,photo-chemical-machining can be used to provide larger features and highresolution ion-etching for finer features.

[0210] Various methods, as described above, can be used to producelayers for a laminated mold. The following examples are given todemonstrate dimensional feature resolution, positional accuracy, and/orfeature accuracy of the layers.

[0211] Ion etching: when using a Commonwealth Scientific Millitron 8000etching system, for example, a uniform etch area of 18 inches by 18inches is achievable. Feature widths from 0.5 microns and above areattainable, depending on the lithographic masks and imaging techniquesused. A feature, for example a 5 micron wide slot, etched to a depth of10 microns can be etched to a tolerance of +−1.25 microns in width, and+−0.1 microns in depth. The positional tolerance of features would bethe same as those produced on the lithographic masks.

[0212] Photo-chemical-machining: when using an Attotech XL 547 etchingsystem, for example, a uniform etch area of 20 inches by 25 inches isachievable. Etched through-feature widths from 20 microns and above areattainable, with solid features widths of 15 microns and above alsobeing attainable. A feature, for example a 30 micron diameter etchedthrough 25 microns of copper, can be etched to a tolerance of +−2.5microns or 10% of the foil thickness. The positional tolerance of suchfeatures would be the same as those produced on the lithographic masks.

[0213] Laser micromachining: when using a PIVOTAL laser micromachiningsystem, for example, a uniform machining area of 3 inches by 3 inches isachievable. Machined through-feature sizes from 5 microns and above areattainable. A feature, for example a 5 micron wide slit machined through25 microns of stainless steel, can be machined to a tolerance of +−1micron. Positional tolerance of +−3 microns is achievable over the 3inch by 3 inch area.

[0214] Electro-forming: depending on the size limitations of thephotographic masks used for this process, electro-forming over areas aslarge as 60 inches by 60 inches is attainable. Electro-formed layershaving thickness of 2 microns to 100 microns is achievable. A feature,for example a 5 micron wide slit, 15 microns deep, can be formed to atolerance of +−1 micron. Positional tolerance of features would be thesame as those produced on the lithographic masks. Layer Assembly andLamination

[0215] As described above, in certain exemplary embodiments of thepresent invention, layers can be designed and produced so that featureshape and placement from layer to layer define the desired geometryalong the X-, Y-, and/or Z-axes of a mold. The total number (andthickness) of layers in the assembly can define the overall height andaspect ratio of the feature. A feature can be either the solid shape orthe space between given structural components.

[0216] What follows are several exemplary methods of bonding the layerstogether to form the laminated mold. One exemplary method used to bondlayers together is a metal-to-metal brazing technique. This techniquecan provide a durable mold that can survive high volume productioncasting and/or can provide efficient release properties from thecastings. Prior to assembly, the layers can have 0.00003 inches of aeutectic braze alloy deposited on the top and bottom surfaces of thelayers, using standard electroplating techniques. An example of a brazematerial is CuSil™, which is comprised of copper and silver, with thepercentage of each being variable for specific applications. CuSil™ canbe designed specifically to lower the temperatures needed to flow thealloy during the brazing process.

[0217] One of the potential concerns during the laminating process is tomaintain accurate registration of the assembly layers, and/or controlthe movement of the layers and the bonding fixture when brought to theelevated temperatures needed to flow the braze material. Several methodscan be used to achieve this registration and/or control. The first caninvolve the practice of having two or more alignment features on thelayers. FIG. 27 is a perspective view of a plurality of exemplary layers27000. As illustrated in FIG. 27, one such alignment feature can be adiameter 27010, and the other alignment feature can be an elongated slot27020. The slot and the diameter can be positioned on each layer onehundred eighty degrees opposed, for example, and can be parallel inorientation with the grain and/or perpendicular to the plane of thelayer material.

[0218]FIG. 28 is a perspective view of an exemplary laminating fixture28000, which can be fabricated from graphite, for example, and can havetwo graphite diameter pins 28010 that can be fixed to the laminationfixture at the same distance apart as the diameter 27010 and slot 27020on the etched layers 27000. The layers can be placed over the pins 28010so that each layer is orientated accurately to the layer below, usingthe slot and diameter to align each layer. Alternatively, two or morediameters can be provided on the layers 27000, each of which correspondsto a pin of laminating fixture 28000.

[0219] During the brazing process, the layered assembly can be heated ina hydrogen atmosphere to a temperature of 825 degrees Celsius, which cancause the CuSil™ braze to flow. As the temperatures elevate, the layersand the fixture material can expand. The slotted alignment feature 27020can allow the fixture 28000 material to expand or move at a dissimilarrate than the layers, by the presence of the elongated slot on the layer27000. The slot 27020 can be greater in length than the diameter of pin28010 in the fixture. The additional length of the slot can bedetermined by the different coefficient for expansion between thegraphite and the assembly layers.

[0220] Other methods for maintaining the layer alignment during a heatedbonding process can include fabricating the bonding fixture from thesame material as the assembly layers, which can thus limit thedissimilar movement of the layers and fixture. The alignment and bondingfixture can also be made so that the alignment pins fit nearly perfectlyto alignment features on the layers, but the pins in the fixture areallowed to float while being held perpendicular to the face of thealignment fixture.

[0221] In order to minimize positional errors when bonding layers(stacking errors), tolerances on certain features can be controlled.Referring to FIG. 27, the positional accuracy of features 27010 and27020 can be controlled by the photographic masks used to produce thelayers (exemplary tolerances for masks are provided in the sectiontitled “Lithographic Techniques”, above). The geometric size andtolerance of features 27010 and 27020 can be governed by the layerthickness and/or micromachining method used to produce them (exemplarytolerances for various micromachining techniques are provided in thesection titled “Layer Machining and Material Options”, above).

[0222] When producing a laminated mold, numerous factors can be aninfluence on the overall tolerances of the features of the mold and/orthe casting. For example, when using a stacking fixture, any of thelaminating fixture's surface flatness, the laminating fixture'sperpendicularity, and the laminating fixture's parallelism can be aninfluence. Also, the dimensional tolerance of the alignment feature(s)of a layer and/or the positional tolerance of that feature(s) can be aninfluence. For example, if an alignment pin, protrusion, or other “male”feature will engage a corresponding hole, indentation, or “female”feature to assist in aligning two or more layers, the dimensionaltolerance and/or vocational tolerance of male and/or female feature canbe an influence on the overall tolerances.

[0223] For example, referring to FIG. 28, bonding fixture 28000 caninclude alignment pins 28010 fitted into the top surface of fixture28000. In a particular experiment, through the use of a surface grindingprocess, followed by a planetary lapping and polishing process, thesides and top surface of bonding fixture 28000 were parallel andperpendicular to a tolerance of +−2 microns, with the top surface finishbeing optically flat to +− one half the wavelength of visible light (400to 700 nanometers), or about 200 to 350 nanometers. The positionalaccuracy of the alignment pins and the machined diameters throughfixture 28000 was +−5 microns, and the pins were perpendicular to thesurface of the fixture to +−2 microns, measured at a pin height of 2 to5 millimeters. The surface of the described fixture measured 6×6 inches,and was produced using an SIP 5000 Swiss jig boring milling center.Hardened steel alignment pins, having a diameter of 0.092 inches, wereprecisely ground to a tolerance of +−1.25 microns using a standardgrinding operation.

[0224] The process of laminating the layers can include placing theprocessed layers over the alignment pins until the desired number oflayers have been assembled. The assembled layers and fixture then can beplaced in a brazing furnace with uniform weight applied to the top ofthe fixture. The furnace temperature can be raised to a temperature of825 degrees Celsius, in a hydrogen atmosphere (a vacuum atmosphere hasalso been shown to work) for 45 minutes. This temperature can besufficient to allow the braze material to uniformly flow and connect thelayers together at all contact points. The fixture then can be cooled inthe hydrogen atmosphere for 2 hours and removed for disassembly. Thegraphite pins can be removed, freeing the bonded structure from thelamination fixture.

[0225] The brazed lamination now can be ready for the final processstep, which can be to coat the entire assembly with a hard nickelsurface. The nickel coating can be applied to the laminated assemblyusing electro-plating techniques, which can deposits 0.0001 inches ofnickel. The nickel-plated surface can act as an interface material thatcan enhance the release and durability properties of the assembled mold.

[0226] Another exemplary method that can be used to bond layers can makeuse of a thermo-cured epoxy rather than metal-to-metal brazing. Prior toassembly, the layers can be coated with an epoxy, MAGNA-TAC® model E645,diluted 22:1 with acetone. The thinned epoxy can be applied to the topand bottom surfaces of the layers using a standard atomizing spray gun.The layers can be spray coated in such a way that the coverage of theepoxy will bond the layers without filling the micro-machined features.A dot coverage of 50% has shown to work. The parameters for dilution andcoverage can be provided by the epoxy manufacture, such as the BeaconChemical Company.

[0227] The layers then can be assembled to a bonding fixture using, forexample, the same technique described in the braze process. Theassembled fixture then can be placed in a heated platen press, such as aCarver model #4122. The assembled layers and fixture can be compressedto 40 pounds per square inch and held at a temperature of 350 degrees F.for 3 hours, and allowed to cool to room temperature under constantpressure. The assembly then can be removed from the fixture using, forexample, the same technique used for the brazed assembly.

[0228] In certain embodiments, the technique described in the secondexample can be considerably less expensive and time consuming than thatused for the first. Using the epoxy process, savings can be realized dueto the cost of the plating and the additional requirement imposed by thehydrogen braze process compared to epoxy stack laminating. The masterderived from the first example can provide more efficient de-moldingproperties and also can survive a greater number of castings than theepoxy bonded mold. The epoxy-bonded mold can demonstrate a costeffective alternative to brazing and can be used for prototyping or whensmaller production quantities are required.

[0229] Casting and Molding Process

[0230] Exemplary embodiments of the present invention can involve thecreation of a high-resolution casting mold, having high-aspect-ratio, aswell as 3-dimensional features and shapes. A precision stack lamination,comprised of micro-machined layers, can be used as a laminated mold. Thelaminated mold can be used to produce advanced micro-devices andstructures (a.k.a., “micro-electro-mechanical structures” and “MEMS”)and/or can be used to create second (or greater) generation derivedmolds.

[0231] The following paragraphs describe the casting process in terms ofthe materials, fixtures, and/or methods that can be used to producesecond-generation molds and final castings.

[0232] Mold Duplication and Replication

[0233] For certain exemplary embodiments of the present invention, theprocess options for producing molds and cast parts can be numerable. Forexample, molds can be made as negative 4010 or positive 4020replications of the desired cast part as shown in FIG. 4. If the mold ismade as a positive, a second-generation mold can be created. If the moldis made as a negative, the final part can be cast directly from themold.

[0234] For certain exemplary embodiments of the present invention, theprocess used to create the layers for the laminated mold can be adetermining factor. For example, some production situations can requirea second-(or even third) generation derived version of the laminatedmold.

[0235] In certain situations, process parameters can be greatly enhancedby combining molding and casting materials having certain predeterminedvalues for physical properties such as durometer, elasticity, etc. Forexample, if the cast part is extremely rigid, with poor releaseproperties, a second-generation consumable mold can be used to createthe final casting. Further specific examples of this practice, and howthey relate to 3-dimensional micro-fabrication are described later inthis document.

[0236] Feature size and positional accuracy for molds and produced partscan be compensated for at the layer production stage of the process. Forexample, known material properties such as thermal expansion orshrinkage can be accurately accounted for due to, for example, theaccuracy levels of the photographic masks and/or laser machining used toproduce mold layers. Feature resolution, using various mold making andcasting materials, can be accurately replicated for features having asize of 1 micron and greater. Surface finishes have also been reproducedand accurately replicated. For example, layers have been used to form alaminated mold which was used to produce a derived silicone RTV mold.The surface finish of a 0.0015 inch thick stainless steel layer(specified finish as 8-10 micro inches RA max) and a 0.002 inch thickcopper layer (specified finish as 8-20 micro inches RA max) were easilyidentified on the molded surfaces of the derived RTV mold. The surfaceswere observed at 400×magnification using a Nikon MM11 measuring scope.The same surface finishes were also easily identified when cast partswere produced from the derived mold using a casting alloy CERROBASE™.Very smooth surface finishes, such as those found on glass, have alsobeen reproduced in molds and castings.

[0237] Materials for Molds and Castings

[0238] For certain exemplary embodiments of the present invention, therecan be hundreds, if not thousands of material options for mold makingand casting. Described below are some potential considerations regardingthe selection of mold and casting materials that can meet therequirements of, for instance, 3-dimensional MEMS.

[0239] To insure the accuracy and repeatability of certain castmicro-devices, the casting material can have the capability to resolvethe fine 3-dimensional feature geometries of the laminated mold. Typicaldimensions of MEMS can range from microns to millimeters. Otherstructures having micro features can have much larger dimensions.

[0240] For certain embodiments, the mold's cavity geometry can influencethe release properties between the mold and the casting, therebypotentially implicating the flexibility (and/or measured durometer) ofthe materials used. Other material compatibility issues also can beconsidered when using a casting process.

[0241] Certain exemplary embodiments of a process of the presentinvention have been developed in order to enable the production of3-dimensional micro-structures from a wide range of materials, tailoredto specific applications. The ability to use various materials for moldsand castings can greatly expand the product possibilities using thistechnique.

[0242] One material that has been successfully used for creatingcastings from a laminated mold is an elastomeric product, referred togenerally as RTV silicone rubber, although other materials could also besuccessful depending on process or product requirements. A wide range ofsilicone-based materials designed for various casting applications arecommercially available through the Dow Corning Corporation of Midland,Mich. For example, the Silastic® brand products have proven successful,possibly because of their resolution capability, releasecharacteristics, flexibility, durability, and/or the fact that they workin a wide range of process temperatures.

[0243] Although other types of silicone rubber products could be used,each of the Dow Corning Silastic® brand products that have been usedconsists of two components; a liquid silicone rubber and a catalyst orcuring agent. Of the Dow Corning Silastic® brand products, there are twobasic curing types: condensation, and addition cure. The two types canallow for a range of variations in material viscosities and cure times.The three primary products used in the earliest tests are Silastic® JRTV Silicone Rubber, Silastic® M RTV Silicone Rubber, and Silastic® SRTV Silicone Rubber. Product specifications are provided in several ofthe examples at the end of this document.

[0244] The Dow Corning Silastic® products used thus far have similarspecifications regarding shrinkage, which increases from nil up to 0.3percent if the silicone casting is vulcanized. Vulcanization can beaccomplished by heating the silicone to a specific elevated temperature(above the casting temperature) for a period of 2 hours. Vulcanizing canbe particularly useful when the casting is to be used as a regeneratedmold, and will be subjected to multiple castings.

[0245] In addition to RTV silicone rubber, urethanes and other materialsalso have properties that can be desirable for laminated molds, derivedmolds, and/or castings, depending on the specific requirement. Forexample, when producing certain 3-dimensional micro-structures withextreme aspect ratios, very fine features, or extreme under-cuts,de-molding can be difficult. In certain situations, the rigidity of themold also can be relevant, especially in certain cases where moldfeatures have high-aspect ratios. For example, the practice ofsacrificing or dissolving laminated second or third generation molds canbe used when castings require very rigid molds, and/or where thede-molding of castings becomes impossible.

[0246] There are several families of materials that can be used forproducing laminated molds, derived molds, and/or final cast devicesincluding, for example:

[0247] Acrylics: such as, for example, PMMA acrylic powder, resins,and/or composites, as well as methacrylates such as butyl, lauryl,stearyl, isobutyl, hydroxethyl, hydroxpropyl, glycidyl and/or ethyl,etc.

[0248] Plastic polymerics: such as, for example, ABS, acetyl, acrylic,alkyd, flourothermoplastic, liquid crystal polymer, styreneacrylonitrile, polybutylene terephthalate, thermoplastic elastomer,polyketone, polypropylene, polyethylene, polystyrene, PVC, polyester,polyurethane, thermoplastic rubber, and/or polyamide, etc.

[0249] Thermo-set plastics: such as, for example, phenolic, vinyl ester,urea, and/or amelamine, etc.

[0250] Rubber: such as, for example, elastomer, natural rubber, nitrilerubber, silicone rubber, acrylic rubber, neoprene, butyl rubber,flurosilicone, TFE, SBR, and/or styrene butadiene, etc.

[0251] Ceramics: such as, for example, silicon carbide, alumina, siliconcarbide, zirconium oxide, and/or fused silica, calcium sulfate,luminescent optical ceramics, bio-ceramics, and/or plaster, etc.

[0252] Alloys: such as, for example, aluminum, copper, bronze, brass,cadmium, chromium, gold, iron, lead, palladium, silver, sterling,stainless, zinc platinum, titanium, magnesium, anatomy, bismuth, nickel,and/or tin, etc.

[0253] Wax: such as, for example, injection wax, and/or plasticinjection wax, etc.

[0254] There can be many material options within these groups that canbe utilized when employing certain embodiments of the present invention.For example, in certain embodiments, metals and metal alloys can beprimarily used as structural materials of final devices, but also canadd to function. Exemplary functional properties of metals and/or alloyscan include conductivity, magnetism, and/or shape memory.

[0255] Polymers also can be used as structural and/or functionalmaterials for micro-devices. Exemplary functional properties can includeelasticity, optical, bio-compatibility, and/or chemical resistivity, toname a few. Materials having dual (or more) functionality, oftenreferred to as engineered “smart” materials, could be incorporated intoa final molded product or a mold. Additional functionality could utilizeelectrostatic, mechanical, thermal, fluidic, acoustic, magnetic,dynamic, and/or piezo-electric properties. Ceramics materials also canbe used for applications where specialty requirements may be needed,such as certain high-temperature environments. Depending on the materialthat is chosen, there can be many alternative methods to solidify thecasting material. The term “solidify” includes, but is not limited to,methods such as curing, vulcanizing, heat-treating, and/or chemicallytreating, etc.

[0256] Mold Fixtures, Planar and Contoured

[0257] For certain exemplary embodiments of the present invention, therecan be a wide range of engineering options available when designing acasting mold. The casting process and geometry of the final product candetermine certain details and features of the mold. Options can beavailable for filling and/or venting a mold, and/or for releasing thecasting from the mold.

[0258] Two basic approaches have been used for demonstrating the certainexemplary methods for mold design and fabrication. These approaches canbe categorized as using a single-piece open-face mold or a two-partclosed mold.

[0259] In certain exemplary embodiments of the present invention, eachof the mold types can include inserting, aligning, and assembling thelaminated mold (or duplicate copy) in a fixture. The fixture can serveseveral purposes, including bounding and/or defining the area in whichto pour the casting material, capturing the casting material during thecuring process, allowing the escape of air and/or off-gases while thecasting material is degassed, and/or enabling mechanical integrationwith the casting apparatus.

[0260] The fixture can be configured in such a way that all sidessurrounding the mold insert are equal and common, in order to, forexample, equalize and limit the effects of thermal or mechanicalstresses put on the mold during the casting process. The mold fixturealso can accommodate the de-molding of the casting.

[0261] Certain exemplary embodiments of this method can provide theability to mold 3-dimensional structures and surfaces on contouredsurfaces. The basic technique is described earlier in this document inthe design parameter section. One element of the technique can be aflexible mold insert that can be fixed to a contoured surface as shownin FIGS. 19 and 22. The mold insert can be made with a membrane orbacking thickness that can allow for integration with various fixtureschemes that can define the contoured shape.

[0262] For non-planar molds, the contour of the mold fixture can beproduced by standard machining methods such as milling, grinding, and/orCNC machining, etc. The flexible mold insert can be attached to thesurface of the mold using any of several methods. One such method is toepoxy bond the flexible insert to the fixture using an epoxy that can beapplied with a uniform thickness, which can be thin enough toaccommodate the mold design. Other parameters that can be consideredwhen choosing the material to fix a membrane to a fixture includedurability, material compatibility, and/or temperature compatibility,etc. A detailed description of a non-planar mold is given as an examplefurther on.

[0263] Casting and Molding Processes

[0264] Various techniques can be used for injecting or filling cavitymolds with casting materials, including injection molding, centrifugalcasting, and/or vibration filling. An objective in any of thesetechniques can be to fill the cavity with the casting material in such away that all of the air is forced out of the mold before the castmaterial has solidified. The method used for filling the cavity mold candepend on the geometry of the casting, the casting material, and/or therelease properties of the mold and/or the cast part.

[0265] As has been described earlier, an open face mold, using flexibleRTV rubber has been found to work effectively. In certain embodiments,an open face mold can eliminate the need for having carefully designedentrance sprue and venting ports. The open face mold can be configuredto create an intermediate structure that can have a controlled backingthickness which can serve any of several purposes: 1) it can be an opencavity section in the casting mold which can serve as an entrance pointin which to fill the mold; 2) it can serve as a degassing port for theair evacuation during the vacuum casting process; 3) it can create abacking to which the cast part or parts can be attached and/or which canbe grasped to assist in de-molding the casting from the flexible mold.

[0266] In casting processes in which the casting material is heated, themold temperature and the cooling of the casting can be carefullycontrolled. For example, when casting a lead casting alloy such asCERROBASE, the alloy can be held at a temperature of 285 degrees F.,while the mold material can be preheated 25-30 degrees higher (310-315degrees F.). The molten alloy can be poured and held at or above themelting point until it is placed in the vacuum environment. The moldthen can be placed in a vacuum bell jar, and held in an atmosphere of 28inches of mercury for 3-4 minutes. This can remove any air pockets fromthe molten metal before the alloy begins to solidify. As soon as the airhas been evacuated, the mold can be immediately quenched or submersed incold water to rapidly cool the molten metal. This can help minimizeshrinkage of the cast metal.

[0267] In certain exemplary embodiments of the present invention, novent holes or slots are provided in the mold, and instead, air can beevacuated from the mold prior to injection. In certain exemplaryembodiments of the present invention, temperature variation and itseffect on the micro-structure can be addressed via enhanced heating andcooling controls in or around the mold. In certain exemplary embodimentsof the present invention, heat can be eliminated from the curing processby replacing the molding materials with photo-curing materials.

[0268] Some of the methods that can be used for micro-molding andcasting include micro-injection molding, powder injection molding, metalinjection molding, photo molding, hot embossing, micro-transfer molding,jet molding, pressure casting, vacuum casting, and/or spin casting, etc.Any of these methods can make use of a laminated or derived moldproduced using this method.

[0269] De-Molding and Finish Machining

[0270] A controlled backing thickness can be incorporated into thecasting to create an intermediate structure. One purpose of theintermediate can be to create a rigid substrate or backing, that allowsthe casting to be grasped for removal from the mold without distortingthe casting. The thickness of the backing can be inversely related tothe geometry of the pattern or features being cast. For example, finegrid patterns can require a thicker backing while coarse patterns canhave a thinner backing. The backing can be designed to have a shape andthickness that can be used to efficiently grasp and/or pull the castpart from the mold.

[0271] Following de-molding, the intermediate can be machined to removethe backing from the casting. Because the thickness of the backing canbe closely controlled, the backing can be removed from the caststructure by using various precision machining processes. Theseprocesses can include wire and electrode EDM (electrode dischargemachining), surface grinding, lapping, and/or fly cutting etc.

[0272] In instances where extremely fine, fragile patterns have beencast, a dissolvable filler or potting material can be poured and curedin the cast structure prior to the removal of the backing from the grid.The filler can be used to stabilize the casting features and eliminatepossible damage caused by the machining process. The filler can beremoved after machining-off the backing. A machinable wax has been foundto be effective for filling, machining, and dissolving from the casting.

[0273] In some part designs, de-molding the casting from the mold mightnot be possible, due to extreme draft angles or extremely fine features.In these cases, the mold can remain intact with the cast part or can besacrificed by dissolving the mold from casting.

EXAMPLES

[0274] A wide range of three-dimensional micro-devices can be fabricatedthrough the use of one or more embodiments of various fabricationprocesses of the present invention, as demonstrated in some of thefollowing examples.

Example 1 Sub-Millimeter Feedhorn Array

[0275] This example demonstrates fabrication of an array of complex3-dimensional cavity features having high aspect ratio. This examplemakes use of a second-generation derived mold for producing the finalpart, which is an array of sub-millimeter feedhorns. A feedhorn is atype of antenna that can be used to transmit or receive electromagneticsignals in the microwave and millimeter-wave portion of the spectrum. Athigher frequencies (shorter wavelengths) the dimensions can become verysmall (millimeters and sub-millimeter) and fabrication can becomedifficult.

[0276] Using certain exemplary embodiments of the present invention, asingle horn, an array of hundreds or thousands of identical horns,and/or an array of hundreds or thousands of different horns can befabricated.

[0277]FIG. 29 is a top view of stack lamination mold 29000 that definesan array of cavities 29010 for fabricating feedhorns. FIG. 30 is across-section of a cavity 29010 taken along section lines 30-30 of FIG.29. As shown, cavity 29010 is corrugated, having alternating cavityslots 30010 separated by mold ridges 30020 of decreasing dimensions,that can be held to close tolerances.

[0278] In an exemplary embodiment, an array of feedhorns contains onethousand twenty identical corrugated feedhorns, each designed to operateat 500 GHz, and the overall dimensions of the feed horn array are 98millimeters wide by 91 millimeters high by 7.6 millimeters deep. Thefabrication of this exemplary array can begin with the creation of alaminated mold, comprised of micro-machined layers, and assembled into aprecision stack lamination.

[0279] Step 1: Creating the laminated mold: The laminated mold in thisexample was made of 100 layers of 0.003″ thick beryllium copper (BeCu)sheets that were chemically etched and then laminated together using anepoxy bonding process. Infinite Graphics, Inc. of Minneapolis, Minn. wascontracted to produce the photo-masks needed for etching the layers. Themasks were configured with one thousand twenty diameters having acenter-to-center spacing of 2.5 millimeters. An IGI Lazerwrite photoplotter was used to create the masks, which were plotted on silverhalite emulsion film. The plotter resolution accuracy was certified to0.5 micrometers and pattern positional accuracy of plus or minus 0.40micrometers per lineal inch. The layers were designed so that horndiameters were different from layer to layer, so that when the layerswere assembled, the layers achieved the desired cross-section taper,slot, and ridge features shown in simplified form in FIG. 30. A total of100 layers were used to create a stacked assembly 7.6 millimeters thick.The layers were processed by Tech Etch, Inc. of Plymouth, Mass., usingstandard photo-etching techniques and were etched in such a way that thecross-sectional shape of the etched walls for each layer areperpendicular to the top and bottom surfaces of the layer (commonlyreferred to as straight sidewalls).

[0280] In this example, the method chosen to bond the etched layerstogether used a thermo-cured epoxy (MAGNA-TAC model E645), using theprocess and fixturing described earlier in the section on layer assemblyand lamination. The assembled fixture was then placed in a 12 inch×12inch heated platen press, Carver model No. 4122. The fixture wascompressed to 40 pounds per square inch and held at a temperature of 350degrees F. for 3 hours, then allowed to cool to room temperature underconstant pressure. The assembly was then removed from the fixture andthe alignment pins removed, leaving the bonded stack lamination. Thelaminated mold (stack lamination) was then used to produce the finalcasting mold.

[0281] Step 2: Creating the casting mold: The second step of the processwas the assembly of the final casting mold, which used the precisionstack lamination made during step 1 as a laminated mold. The castingmold created was a negative version of the lamination, as shown inperspective view for a single feed horn 31000 in FIG. 31. Also shown isa feedhorn ridge 31010 that can correspond to a cavity slot 30010, and afeedhorn base 31020.

[0282] For this example, Silastic® J RTV Silicone Rubber was used tomake the final casting mold. This product was chosen because it isflexible enough to allow easy release from the laminated mold withoutdamaging the undercut slots and rings inside the feedhorns, and becauseof its high-resolution capability. Described below are the productspecifications.

[0283] Silastic® J: Durometer Hardness: 56 Shore A points TensileStrength, psi: 900 Linear Coefficient of Thermal Expansion: 6.2 × 10⁻⁴Cure Time at 25 C.: 24 hours

[0284] The Silastic® J Silicone RTV was prepared in accordance with themanufacturer's recommendations. This included mixing the silicone andthe curing agent and evacuating air (degassing) from the material priorto filling the mold-making fixture. At the time the example wasprepared, the most effective way of degassing the Silicone prior tofilling the mold fixture was to mix the two parts of the Silicone andplace them in a bell jar and evacuate the air using a dual stage vacuumpump. The material was pumped down to an atmosphere of 28 inches ofmercury and held for 5 minutes beyond the break point of the material.The Silicone was then ready to pour into the mold fixture.

[0285] As shown in the side view of FIG. 32, an open-face fixture 32000was prepared, the fixture having a precision-machined aluminum ring32010, precision ground glass plate 32030, rubber gaskets 32040, 32050and the laminated mold 32060. The base 32020 of the fixture was thickPlexiglas. On top of the Plexiglas base was a glass substrate 32030.Rubber gasket 32040 separated the glass base and the glass substrate. Anadditional rubber gasket 32050 was placed on the top surface of theglass substrate 32030 and the laminated mold 32060 was placed on the topgasket. The rubber gaskets were used to prevent unwanted flashing ofmaterial during casting. A precision-machined aluminum ring 32010 wasplaced over the laminated mold subassembly and interfaced with the lowerrubber gasket 32040.

[0286] Generally, the height of the ring and dimensions of the abovepieces can depend upon the dimensions of the specific structure to becast. The ring portion 32010 of the fixture assembly served severalpurposes, including bounding and defining the area in which to pour moldmaterial, capturing the material during the curing process, andproviding an air escape while the mold material was degassed usingvacuum. The fixture was configured in a way that all sides surroundingthe laminated mold 32060 were equal and common, in order to equalize andlimit the effects of thermal or mechanical stresses put on thelamination from the mold material.

[0287] An open-face mold was used for this example. The mold insert andmolding fixture were assembled and filled with the silicone RTV, thenthe air was evacuated again using a bell jar and vacuum pump in anatmosphere of 28 inches of mercury. After allowing sufficient time forthe air to be removed from the silicone, the mold was then heat-cured byplacing it in a furnace heated to and held at a constant temperature of70 degrees F. for 16 hours prior to separating the laminated mold fromthe derived RTV mold. The molding fixture was then prepared fordisassembly, taking care to remove the laminated mold from the RTV moldwithout damaging the lamination, since the lamination can be usedmultiple times to create additional RTV molds.

[0288] The resulting RTV mold was a negative version of the entirefeedhorn array consisting of an array of one thousand twenty negativefeedhorns, similar to the simplified single horn 31010 shown inperspective view in FIG. 31.

[0289] Step 3: Casting the feedhorn array: In this example, the castfeedhorn arrays were made of a silver loaded epoxy, which iselectrically conductive. In certain exemplary embodiments of the presentinvention, binders and/or metallic (or other) powders can be combinedand/or engineered to satisfy specific application and/or processspecifications. The conductive epoxy chosen for this example providedthe electrical conductivity needed to integrate the feedhorn array withan electronic infrared detector array.

[0290] The conductive epoxy was purchased from the company BONDLINETM ofSan Jose, Calif., which designs and manufactures engineered epoxiesusing powdered metals. Certain of its composite metal epoxies can becured at room temperature, have high shear strength, low coefficient ofthermal expansion, and viscosities suited for high-resolution casting.

[0291] Exemplary embodiments of the present invention can utilizevarious techniques for injecting or filling cavity molds with castingmaterials. In this example, a pressure casting method was used.

[0292] The BONDLINE™ epoxy was supplied fully mixed and loaded with thesilver metallic powder, in a semi-frozen state. The loaded epoxy wasfirst normalized to room temperature and then pre-heated per themanufacturer's specification. In the pre-heated state the epoxy wasuncured and ready to be cast. The uncured epoxy was then poured into theopen-face mold to fill the entire mold cavity. The mold was then placedin a pressurized vessel with an applied pressure of 50 psi using drynitrogen, and held for one hour, which provided sufficient time for theepoxy to cure. The mold was then removed from the pressure vessel andplaced in an oven for 6 hours at 225 degrees F., which fully cured theconductive epoxy.

[0293] Step 4. Demolding and finish machining: After the cast epoxy hadbeen cured, it was ready for disassembly and demolding from the castingfixture and mold. The mold material (RTV silicone) was chosen to beflexible enough to allow the cast feedhorn array to be removed from thecasting mold without damaging the undercuts formed by the slots andridges. When done carefully, the mold could be reused several times tomake additional feedhorn arrays.

[0294] The backing thickness 31020 of the RTV mold shown in FIG. 31 cameinto play during the de-molding process. The backing was cast thickenough to allow easy grasping to assist with separating the casting moldfrom the cast piece. In this example, the RTV casting mold was flexibleand allowed easy separation without damaging the undercut slots andrings inside the cast feedhorns.

[0295] Depending on the piece being cast, machining, coating, and/orother finish work can be desirable after de-molding. In this example, afinal grinding operation was used on the top surface (pour side of themold) of the feedhorn array because an open face mold was used. Thisfinal grinding operation could have been eliminated by using a closed,two-part mold.

Example 2 Individual Feedhorns Produced in a Batch Process

[0296] This example makes use of certain exemplary embodiments of thepresent invention to demonstrate the production of sub-millimeterfeedhorns in a batch process. The example uses the same part design andfabrication process described in example 1, with several modificationsdetailed below.

[0297] Process Modifications: The process detailed in example 1 was usedto produce an array of one thousand twenty feedhorns. The firstmodification to the process was the casting material used to produce thearray. The casting material for this example was a two-part castingpolymer sold through the Synair Corporation of Chattanooga, Tenn.Product model “Mark 15 Por-A-Kast” was used to cast the feedhorn arrayand was mixed and prepared per the manufacturer's specifications. Thepolymer was also cast using the pressure filling method described inexample 1.

[0298] The next modification was a surface treatment applied to the castpolymer array. A conductive gold surface was deposited onto the polymerarray in order to integrate the feedhorns with the detector electronics.The gold surface was applied in two stages. The first stage was theapplication of 0.5 microns of conduction gold, which was sputter-coatedusing standard vacuum deposition techniques. The first gold surface wasused for a conductive surface to allow a second stage electro-depositionor plating of gold to be applied. The second gold plating was appliedwith a thickness of 2 microns using pure conductive gold.

[0299] The final modification was to dice or cut the feedhorns from thecast and plated array into individual feedhorns, that were then suitablefor detector integration. A standard dicing saw, used for wafer cutting,was used to cut the feedhorns from the cast array.

Example 3 Array of 3-Dimensional Micro-Structures

[0300] Process steps 1 and 2 described in example 1 were used to producea large area array of micro-structures, which are described as negativesof the feedhorn cavities, shown as a single feedhorn in FIG. 31. Thelaminated mold and molding fixture was used to cast the micro-structuresusing Dow Corning's Silastic® M RTV Silicone Rubber. This product waschosen because it is flexible enough to release from the mold insert,without damaging the circular steps in the structure, but has thehardness needed to maintain the microstructures in a standing positionafter being released from the mold. Described below are the productspecifications.

[0301] Silastic® M Durometer Hardness: 59 Shore A points TensileStrength, psi: 650 Linear Coefficient of Thermal Expansion: 6.2 × 10⁻⁴Cure Time at 25 C.: 16 hours

[0302] The Silicone RTV was prepared in accordance with themanufacturer's recommendations, using the process described earlier inexample 1, step 2. The laminated mold and molding fixture were assembledand filled with the silicone RTV, using the process described earlier inexample 1, step 2. The molding fixture was then prepared fordisassembly, taking care to separate the mold insert from the castsilicone array. The resulting casting was an array consisting of onethousand twenty 3-dimensional micro-structures. The shape and dimensionof a single structure is shown in simplified form in FIG. 31. Example #4

Cylindrical Tubing with Micro-fluidic Channels on the Inside Diameter

[0303] Certain exemplary embodiments of the present invention have beenused to produce a 2.5 centimeter length of clear urethane tubing, having3-dimensional micro-fluid channels on the inside diameter of the tubing.The fluidic tubing was produced using a flexible cavity insert with acontrolled backing thickness. The following example demonstrates how thecavity insert can enable the production of three-dimensional features onthe inside and outside diameters of cylindrical tubing.

[0304] Step 1: Creating the mold insert: The first step in the processwas to fabricate the micro-machined layers used to produce the cavityinsert. The cast tubing was 2.5 centimeters long, having a 3.0millimeter outside diameter and a 2.0 millimeter inside diameter, with50 three-dimensional micro-fluidic channels, equally spaced around theinterior diameter of the tube. FIG. 33 shows a side view of the tubing33000, the wall of which defines numerous fluidic channels 33010.Although each fluidic channel could have different dimensions, in thisexample each channel was 0.075 mm in diameter at the entrance of thechannel from the tube, and each channel extended 0.075 mm deep. Eachchannel tapered to a diameter of 0.050 mm, the taper beginning 0.025 mmfrom the bottom of each channel.

[0305] Photo-chemical machining was used to fabricate the layers for thelaminated mold. FIG. 34 is a top view of a such a laminated mold 34000,which was created using several photo masks, one of which with a similartop view. Mold 34000 includes an array of fluidic channels 34010 In thisparticular experiment, the length of channels 34010 was approximately 25millimeters, and the width of each collection of channels wasapproximately 6.6 millimeters.

[0306]FIG. 35 is a cross-section of mold 34000 taken at section lines35-35 of FIG. 34. To the cross-sectional shape of channel 34010, a firstcopper foil 35010 having a thickness of 0.025 mm, and a second copperfoil 35020 having a thickness of 0.050 mm, were chemically etched andthen laminated together using a metal-to-metal brazing process. Each ofthe layers used in the laminated mold assembly used a separatephoto-mask. The masks used for layer 35020 were configured with a9.50×0.075 mm rectangular open slot, arrayed redundantly in 50 places, aportion of which are illustrated in FIG. 34. To achieve the desiredtaper, two masks were used for layer 35010. The bottom mask wasconfigured with a 9.50×0.075 mm rectangular open slot and the top maskwas configured with a 9.50×0.050 rectangular open slot, each of theslots were also redundantly arrayed in 50 places. The photo-masks wereproduced to the same specifications, by the same vendor as thosedescribed in example 1, step 1.

[0307] The layers were designed so that the slot placement was identicalfrom layer to layer, which when assembled, produced the cross-sectionalshape for the channels as shown in FIG. 35. The final thickness of thelamination was specified at 0.083 millimeters, which required one 0.025layer of copper foil, and one 0.050 thick layer of copper foil, leavinga total thickness amount of 0.002 millimeters for braze material on eachside of each etched layer. The layers were photo-etched by the samevendor, and same sidewall condition as those described in example 1,step 1. The method chosen to bond the grid layers together was ametal-to-metal brazing technique described earlier, in detail as one oftwo exemplary methods of bonding layers together (eutectic braze alloy)

[0308] Step 2: Creating the flexible cavity insert: The next step of theprocess was to create a flexible cavity insert from the brazed layeredassembly. FIG. 36 is a side view of cavity insert 36000, which wasproduced from the brazed assembly with a backing 36010 having athickness of 0.050 millimeters. The cavity insert 36000 was producedusing Silastic® S RTV Silicone Rubber as the base material. The RTVSilicone Rubber was used because of its resolution capability, releaseproperties, dimensional repeatability, and its flexibility to form theinsert to a round pin that would be assembled to the final moldingfixture. The material properties of Silastic™ S are shown below.

[0309] Silastic® S Durometer Hardness: 26 Shore A points TensileStrength, psi: 1000 Linear Coefficient of Thermal Expansion: 6.2 × 10⁻⁴Cure Time at 25 C.: 24 hours

[0310] The casting fixture used to create the RTV cavity insert wassimilar to that shown in FIG. 32 and is described in detail in the priorexamples. A modification was made to the fixture assembly, which was atop that was placed over the pour area of the mold fixture. This top wasplaced and located to close the mold after air evacuation and reduce thebacking thickness 36010 of the RTV insert to a thickness of 0.050millimeters, shown in FIG. 36. The Silastic® S RTV Silicone Rubber usedfor the cavity insert fabrication was prepared in accordance with themanufacturers recommendations, using the process described earlier inexample 1, step 2.

[0311] Step 3: Assembling the molding fixture: The final molding fixturewas then ready to be assembled. The molding fixture included a baseplate (FIG. 37), the cavity inserts (FIG. 38), and a top plate (FIG.40). FIG. 37 is a top view of the base plate 37000, which was made froma 0.25 inch aluminum plate that was ground flat and machined usingstandard CNC machining techniques. The base had six machined diameters37010 through the plate. These six diameters would accept the cavityinsert pins described later. The plate also had machined diametersthrough the plate, which would accept dowel pins 37020 that were used toalign and assemble the top plate and the base plate, as well as 4 boltdiameters 37030 to hold the top and bottom plates together.

[0312]FIG. 38 is a side view of an insert fixture 38000, that includesthe flexible cavity insert 36000 attached to a 3 centimeter long, 1.900millimeter diameter steel pin 38010. The pin 38010 was ground to thedesired dimensions using standard machine grinding techniques. The RTVcavity insert 36000 was cut to the proper size before being attached tothe pin. The RTV insert 36000 was attached to outside diameter of thepin 38010 using a controlled layer of two-part epoxy.

[0313]FIG. 39 is a side view of several insert fixtures 39000 that havebeen attached to a base plate 37000. Each insert 36000 was attached itscorresponding pin 38010 so that the end of pin 38010 could be assembledto a corresponding machined diameter 37010 of base plate 37000 withoutinterference from insert 36000. Once each insert 36000 was attachedaround the diameter of its corresponding pin 38010 and the pin placed inthe corresponding through-diameter of base plate 37010, the pin was heldperpendicular to base plate 37000 and in alignment with a top plate ofthe fixture.

[0314]FIG. 40 is a top view of a top plate 40000 of the fixture, whichwas also fabricated of aluminum and machined using CNC techniques. Therewere six 3.0 millimeter diameters 40010 milled through the thickness ofplate 40000, which was 3.0 centimeters thick. Diameters 40010 definedthe cavity areas of the mold that would be filled during the finalcasting process, and aligned to the pins assembled to the base plate.Also incorporated into the top plate were bolt features 40020 and dowelfeatures 40030 needed to align and assemble the top plate 40000 to thebase plate 37000. The thickness of top plate 40000 was specified toslightly exceed the desired length of the final cast tubing, which wascut to its final length after casting. The casting fixture was thenassembled, first by assembling the cavity insert 38000 to the base plate37000, followed by assembling the top plate 40000 to the base usingbolts and dowels. The top view of a representative cavity section for anassembled fixture is shown in FIG. 19.

[0315] Step 4: Casting the fluidic tubes: Several fluidic tubes wereproduced using the assembled casting fixture. A clear urethane was usedfor the final casting because of its high-resolution, low shrink factor,and transparent properties, which allowed for final inspection of theinterior diameter features through the clear wall of the tube. Thecasting material was purchased from the Alumilite Corporation ofKalamazoo, Mich., under the product name Water Clear urethane castingsystem. The manufacturer described the cured properties as follows:Hardness, Shore D: 82 Density (gm/cc) 1.04 Shrinkage (in/in/) maximum0.005 Cure Time (150 degrees F.) 16 hr

[0316] The urethane was prepared in accordance with the manufacturer'srecommendations. This included the mixing and evacuation of air(degassing) from the material prior to filling the mold. The mosteffective way found for degassing the urethane prior to filling the moldfixture was to mix parts A and B, place them in a bell jar, and evacuatethe air using a dual stage vacuum pump. The mixture was pumped down toan atmosphere of 28 inches of mercury and held for 15 minutes beyond thebreak point of the material The urethane was then ready to pour into themold fixture.

[0317] The assembled mold fixture was heated to 125 degrees F. prior tofilling the cavities with the urethane. The pre-heating of the moldhelped the urethane to flow and fill the cavities of the mold, and aidedin the degassing process. The cavity sections of the mold were thenfilled with the urethane, and the air was evacuated again using a belljar and vacuum pump in an atmosphere of 28 inches of mercury. Afterallowing sufficient time for the air to be removed from the urethane,the mold was then removed from the vacuum bell jar and placed in anoven. The mold was heated and held at a constant temperature of 150-180degrees F. for 16 hours prior to separating the cast tubes from themold. The molding fixture was then disassembled and the cast tubes wereseparated from the cavity inserts. The inserts were first removed fromthe base plate of the fixture. The tubes were easily separated from thecavity insert assembly due to the flexibility and release properties ofthe silicone RTV, combined with the hardness of the urethane tubes.

Example #5 Tubing with Micro-fluidic Channels on the Outside Diameter

[0318] Example #4 described the method used for producing cast urethanetubing with micro-fluidic features on the inside diameter of the tube.The current example demonstrates how that process can be altered toproduce tubing with the micro-fluidic channels on the outside diameterof the tubing. This example uses a similar part design and thefabrication process described in example 4, with several modificationsdetailed below.

[0319] One process modification involved step 3, assembling the moldingfixture. For this step, a modification was made to the fixture designthat enabled the molded features to be similar to that shown in FIGS.20-22. The first modification was in the size of the machined diametersin the base plate and the top plate of the fixture described in example4. The flexible RTV cavity insert that was attached to a pin in example4 was instead attached to the inside diameters of the top fixture plate,similar to that shown in FIG. 22. In order to accommodate the existingRTV cavity insert, the cavity diameters of the top plate were milled toa size of 1.900 millimeters. The RTV cavity insert was then attached tothe milled diameter of the top plate using the same epoxy techniquedescribed in example 4. The base plate of the fixture was also modifiedto accept a 1.0 millimeter diameter pin, and was assembled similar tothe that shown in FIG. 22. The same casting process was used asdescribed in example 4. After following the final casting process, withthe altered molding fixture, the urethane tubes were produced having thesame fluidic channels located on the outside diameter of the cast tube.

[0320] Additional Embodiments—X-Ray and Gamma-Ray Collimators, Grids,and Detector Arrays

[0321] Certain exemplary embodiments of the present invention canprovide methods for fabricating grid structures having high-resolutionand high-aspect ratio, which can be used for radiation collimators,scatter reduction grids, and/or detector array grids. Such devices canbe used in the field of radiography to, for example, enhance imagecontrast and quality by filtering out and absorbing scattered radiation(sometimes referred to as “off-axis” radiation and/or “secondary”radiation).

[0322] Certain embodiments of such devices can be used in nearly everytype of imaging, including astronomy, land imaging, medical imaging,magnetic resonance imaging, tomography, fluoroscopy, non-destructiveinspection, non-destructive testing, optical scanning (e.g., scanning,digital copying, optical printing, optical plate-making, faxing, and soforth), photography, ultra-violet imaging, etc. Thus, certainembodiments of such devices can be comprised in telescopes, satellites,imaging machines, inspection machines, testing machines, scanners,copiers, printers, facsimile machines, cameras, etc. Moreover, thesemachines can process images using analog and/or digital techniques.

[0323] For the purposes of this description, the term “collimator” isused generally to describe what may also be referred to as a radiationcollimator, x-ray grid, scatter reduction grid, detector array grid, orany other grid used in an imaging apparatus and/or process.

[0324] Certain collimators fabricated according to one or more exemplaryembodiments of the present invention can be placed between the objectand the image receptor to absorb and reduce the effects of scatteredx-rays. Moreover, in certain exemplary embodiments, such collimators canbe used in a stationary fashion, like those used in SPECT (Single PhotonEmission Computed Tomography) imaging, or can be moved in areciprocating or oscillating motion during the exposure cycle to obscurethe grid lines from the image, as is usually done in x-ray imagingsystems. Grids that are moved are known as Potter-Bucky grids.

[0325] X-ray grid configurations can be specified by grid ratio, whichcan be defined as the ratio of the height of the grid to the distancebetween the septa. The density, grid ratio, cell configuration, and/orthickness of the structure can have a direct impact on the grid'sability to absorb off-axis radiation and/or on the energy level of thex-rays that the grid can block.

[0326] Certain exemplary embodiments of the present invention can allowfor the use of various materials, including high-density grid materials.Also, certain exemplary can make use of a production mold, which can bederived from a laminated mold.

[0327] Numerous additional aspects can be fabricated according tocertain exemplary embodiments of the present invention. For example, thelaminated mold can be produced from a stack lamination or other method,as discussed above. Moreover, X-ray absorbent material, such as lead,lead alloys, dense metallic composites, and/or epoxies loaded with densemetallic powders can be cast into a mold to produce x-ray absorbinggrids. High-temperature ceramic materials also can be cast using aproduction mold.

[0328] In addition, the open cells of the ceramic grid structure can befilled with detector materials that can be accurately registered to acollimator. The molds and grids can be fabricated having high-resolutiongrid geometries that can be made in parallel or focused configurations.The mold can remain assembled to the cast grid to provide structuralintegrity for grids with very fine septal walls, or can be removed usingseveral methods, and produce an air-cell grid structure.

[0329]FIG. 41 is a block diagram illustrating an exemplary embodiment ofa method 41000 of the present invention Method 41000 can include thefollowing activities:

[0330] 1) creating a lithographic mask 41010 defining the features ofeach unique layer,

[0331] 2) using lithographic micro-machining techniques and/ormicro-machining techniques to produce patterned layers 41020, and

[0332] 3) aligning, stacking, and/or laminating the patterned layers41030 in order to achieve the desired 3-dimensional cavity shape,high-aspect ratios, and/or other device features desired for thelaminated mold 41040,

[0333] 4) fabricating a casting mold 41050 derived from the laminatedmold, and/or

[0334] 5) casting x-ray grids (or other parts) 41060 using the derivedcasting mold.

[0335] The following discussion describes in detail exemplary activitiesinvolved in fabricating certain exemplary embodiments of a laminatedmold, fabricating a derived mold from the laminated mold, and finallycasting a collimator from the derived mold. Certain variations in theoverall process, its activities, and the resulting collimator are notedthroughout.

[0336] In certain exemplary embodiments, the final collimator can becustomized as a result of the casting process. For instance,conventional collimators have two separated flat major sides that areparallel to each other, thereby forming a flat, generally planar gridstructure. Although certain exemplary embodiments of the presentinvention includes methods for forming these collimators, exemplaryembodiments of the invention also can be used to form non-planarcollimators.

[0337] An exemplary embodiment of a method of the present invention canbegin with the acquisition, purchase, and/or fabrication of a firstcollimator. This first collimator can serve as the master collimatorfrom which one or more molds can be formed. The master collimator can bemade by any means, including stack lamination, but there is nolimitation with respect to how the first or master collimator can bemade. Also, as will be explained in more detail, because the mastercollimator is not necessarily going to be a collimator used inradiography, it is possible to customize this master collimator tofacilitate mold formation.

[0338] The mold itself can be fabricated of many materials. When formedof a flexible material, for example, it is possible to use the mold tomake a non-planar collimator. The material of the mold can be customizedaccording to cost and performance requirements. In some embodiments, itis possible to make a mold of material that is substantially transparentto radiation transmission. The mold could be left embedded in the finalcast collimator. This particular variation can be applicable when thefinal collimator has very narrow septal walls and the mold is needed toprovide support and definition for the collimator. The mold generallyalso can be reused to form multiple final (or second) collimators toachieve economies of manufacturing scale.

[0339] Radiation Opaque Casting Materials for Collimators and Grids

[0340] A broad selection of base materials can be used for thefabrication of parts, such as x-ray collimators and scatter reductiongrids. One potential characteristic of a grid material is sufficientabsorption capacity so that it can block selective x-rays or gammaphotons from reaching an image detector. In certain embodiments of thepresent invention, this characteristic can require high density and/orhigh atomic number (high z) materials. Certain exemplary embodiments ofthe present invention can utilize lead, tungsten, and/or various leadalloys for grid fabrication, but also can include the practice ofloading various binders or alloys with dense powder metals, such astungsten. The binders can be epoxies, polymers, and/or dense alloyswhich are described in detail below.

[0341] For certain exemplary embodiments of the present invention, leadcan be used for casting purposes because of its high density and lowmelting point, which can allow the molten lead to be poured or injectedinto a mold. In certain situations, however, pure lead can shrink and/orpull away from molds when it solidifies, which can inhibit the castingof fine features. This can be overcome by using lead alloys, made fromhigh-density materials, which can allow the metal alloy to flow at lowertemperatures than pure lead while reducing shrink factors.

[0342] A typical chief component in a lead alloy is bismuth, a heavy,coarse crystalline metal that can expand by 3.3% of its volume when itsolidifies. The presence of bismuth can expand and/or push the alloyinto the fine features of the mold, thus enabling the duplication offine features. The chart below shows the physical properties of purelead and two lead alloys that were used to produce collimators. Thealloys were obtained from Cerro Metal Products Co. of Bellefonte, Pa.Many other alloys exist that can be used to address specific casting andapplication requirements. MELT DENSITY BASE MATERIAL COMPOSITION POINT(g/cc) Pure Lead Pb 621.7 degrees F. 11.35 CERROBASE ™ 55.5% BI, 44.5%Pb 255 degrees F. 10.44 CERROLOW-117 ™ 44.7% BI, 22.6% Pb, 19.1% In, 117degrees F. 9.16 8.3% Sn, 5.3% Cd,

[0343] The physical properties of lead alloys can be moreprocess-compatible when compared to pure lead, primarily because of themuch lower melting point. For example, the low melt point of CERROBASE™can allow the use of rubber-based molds, which can be helpful whencasting fine-featured pieces. This can be offset in part by a slightlylower density (about 8%). The somewhat lower density, can be compensatedfor, however, by designing the grid structure with an increasedthickness and/or slightly wider septal walls.

[0344] Also, the alloy can be loaded with dense powder metals, such astungsten, gold, and/or tantalum, etc., to increase density. Similarly,epoxy binders can be loaded with a metallic powder such as, for example,powdered tungsten, which has a density of 19.35 grams per cubiccentimeter. In this approach, tungsten particles ranging in size from1-150 microns, can be mixed and distributed into a binder material. Thebinder material can be loaded with the tungsten powder at sufficientamounts needed to achieve densities ranging between 8 and 14 grams percubic centimeter. The tungsten powder is commercially available throughthe Kulite Tungsten Corporation of East Rutherford N.J., in variousparticle sizes, at a current cost of approximately $20-$25 dollars perpound.

[0345] The binders and metallic powders can be combined and engineeredto satisfy specific application and process issues. For example,tungsten powder can be added to various epoxies and used for casting.

[0346] The company BONDLINE™ of San Jose, Calif., designs andmanufactures engineered adhesives, such as epoxies, using powderedmetals. Such composite metal epoxies can be cured at room temperature,can have high shear strength, low coefficient of thermal expansion, andviscosities that can be suited for high-resolution casting. Powderedmaterials combined with epoxy can be stronger than lead or lead alloys,but can be somewhat lower in density, having net density ranging from7-8 grams per cubic centimeter. This density range can be acceptable forsome collimator applications. In applications where material density iscritical the practice of loading a lead alloy can be used. For example,tungsten powder can be combined with CERROBASE™ to raise the net densityof the casting material from 10.44 up to 14.0 grams per cubiccentimeter.

[0347] Certain exemplary embodiments of the present invention alsoinclude the casting of grid structures from ceramic materials, such asalumina, silicon carbide, zirconium oxide, and/or fused silica. Suchceramic grid structures can be used to segment radiation imagingdetector elements, such as scintillators. The Cotronics Corporation ofBrooklyn, N.Y., manufactures and commercially distributes Rescor™Cer-Cast ceramics that can be cast at room temperature, can have workingtimes of 30-45 minutes, can have cure times of 16 hours, and canwithstand temperatures ranging from 2300 to 4000 degrees F.

[0348] Additional Embodiments—Anti-Scatter Grids for Mammography andGeneral Radiography

[0349] One or more exemplary embodiments of the present invention canprovide cellular air cross grids for blocking scattered X-ray radiationin mammography applications. Such cross grids can be interposed betweenthe breast and the film-screen or digital detector. In some situations,such cross grids can tend to pass only the primary,information-containing radiation to the film-screen while absorbingsecondary and/or scattered radiation which typically contains no usefulinformation about the breast being irradiated.

[0350] Certain exemplary embodiments of the present invention canprovide focused grids. Grids can be made to focus to a line or a point.That is, each wall defining the grid can be placed at a unique angle, sothat if an imaginary plane were extended from each seemingly parallelwall, all such planes would converge on a line or a point at a specificdistance above the grid center—the distance of that point from the gridknown as the grid focal distance. A focused grid can allow the primaryradiation from the x-ray source to pass through the grid, producing thedesired image, while the off-axis scattered rays are absorbed by thewalls of the grid (known as septal walls).

[0351] In certain embodiments, the septal walls can be thick enough toabsorb the scattered x-rays, but also can be as thin as possible tooptimize the transmission ratio (i.e., the percentage of open cell areato the total grid area including septal walls) and minimize gridartifacts (the shadow pattern of grid lines on the x-ray image) in theradiograph.

[0352] The relation of the height of the septal walls to the distancebetween the walls can be known as the grid ratio. Higher grid ratios canyield a higher scatter reduction capability, and thus a higher ContrastImprovement Factor (CIF), which can be defined as the ratio of the imagecontrast with and without a grid. A higher grid ratio can require,however, a longer exposure time to obtain the same contrast, thuspotentially exposing the patient to more radiation. This dose penalty,known as the Bucky factor (BF), is given by BF=CIF/Tp, where Tp is thefraction of primary radiation transmitted. Certain exemplary embodimentsof the present invention can provide a grid design that arrives at anoptimal and/or near-optimal combination of these measures.

[0353] One or more exemplary embodiments of the present invention caninclude fine-celled, focused, and/or large area molded cross-grids,which can be sturdily formed from a laminated mold formed of laminatedlayers of metal selectively etched by chemical milling or photo-etchingtechniques to provide open focused passages through the laminated stackof etched metal layers. In certain applications, such molded and/or castcross grids can maximize contrast and accuracy of the resultingmammograms when produced with a standard radiation dosage.

[0354] In certain exemplary embodiments, the laminated mold for themolded cross grids can be fabricated using adhesive or diffusion bondingto join abutting edges of thin partition portions of the laminatedabutting layers with minimum intrusion of bonding material into the openfocused passages.

[0355] Exemplary embodiments of the present invention can utilize any ofa wide number of different materials to fabricate such molded and/orcast cross grids. A specific application can result in any of thefollowing materials being most appropriate, depending on, for example,the net density and the cell and septa size requirements:

[0356] Lead or lead alloy alone can offer a density of 9-11 grams percc;

[0357] Lead alloy can be loaded with a dense composite (e.g., tungsten,tantalum, and/or gold, etc.) powder to form a composite having a densityof 12-15 grams per cc;

[0358] Polymer can be loaded with a dense composite (e.g., lead,tungsten, tantalum, and/or gold, etc.) powder to form a composite havinga density of 8-9 grams per cc;

[0359] The cast grid made of lead alloy or any of the above combinationscan be encapsulated in a low density polymer such that the transmissionis minimally affected but scatter is significantly reduced.

[0360] In addition, certain embodiments of the present invention can beemployed to fabricate grids and/or collimators for which the mold can bepre-loaded with dense powder, followed by alloy or polymer.Alternatively, polymer or alloy can be pre-loaded with dense powder theninjected into the mold. In certain embodiments, the casting can beremoved from a flexible mold. In other embodiments, the mold can bedissolved or consumed to de-mold the casting. In certain embodiments, amaster can be removed layer-by-layer from rigid mold. Alternatively, thelost wax approach can be used in which the model is dissolvable wax,dissolvable PMMA, dissolvable polyurethane, dissolvable high-resolutionceramic, and/or some other dissolvable material.

[0361] Additional Embodiments—Computed Tomography Collimator andDetector Array

[0362] Certain exemplary embodiments of the present invention canprovide a system that includes an x-ray source, a scatter collimator,and a radiation detector array having a plurality of reflectivescintillators. Such a system can be used for computer-assistedtomography (“CT”). Computed tomography is often performed using a CTscanner, which can also be known as a CAT scanner. In certainembodiments, the CT scanner can look like a large doughnut, having asquare outer perimeter and a round hole. The patient can be positionedin a prone position on a table that can be adjusted up and down, and canbe slid into and out of the hole of the CT scanner. Within the chassisof the CT scanner is an x-ray tube on a rotating gantry which can rotatearound the patient's body to produce the images. On the opposite side ofthe gantry from the x-ray tube can be mounted an array of x-raydetectors.

[0363] In certain exemplary embodiments of the present invention, thex-ray source can project a fan-shaped beam, which can be collimated tolie within an X-Y plane of a Cartesian coordinate system, referred to asthe “imaging plane”. The x-ray beam can pass through the object beingimaged, such as a patient. The beam, after being attenuated by theobject, can impinge upon the array of radiation detectors. The intensityof the attenuated beam radiation received at the detector array can bedependent upon the attenuation of the x-ray beam by the object. Eachdetector element of the array can produce a separate electrical signalthat can provide a measurement of the beam attenuation at the detectorlocation. The attenuation measurements from all the detectors can beacquired separately to produce an x-ray transmission profile of theobject.

[0364] For certain exemplary embodiments of the present invention, thedetector array can include a plurality of detector elements, and can beconfigured to attach to the housing. The detector elements can includescintillation elements, or scintillators, which can be coated with alight-retaining material. Moreover, in certain exemplary embodiments,the scintillators can be coated with a dielectric coating to containwithin the scintillators any light events generated in thescintillators. Such coated scintillators can reduce detector elementoutput gain loss, and thereby can extend the operational life of adetector element and/or array, without significantly increasing thecosts of detector elements or detector arrays.

[0365] In certain exemplary embodiments of the present invention, thex-ray source and the detector array can be rotated with a gantry withinthe imaging plane and around the object to be imaged so that the angleat which the x-ray beam intersects the object can constantly change. Agroup of x-ray attenuation measurements, i.e., projection data, from thedetector array at one gantry angle can be referred to as a “view”, and a“scan” of the object can comprise a set of views made at differentgantry angles during one revolution of the x-ray source and detector. Inan axial scan, the projection data can be processed to construct animage that corresponds to a two-dimensional slice taken through theobject.

[0366] In certain exemplary embodiments of the present invention, imagescan be reconstructed from a set of projection data according to the“filtered back projection technique”. This process can convert theattenuation measurements from a scan into integers called “CT numbers”or “Hounsfield units”, which can be used to control the brightness of acorresponding pixel on a cathode ray tube display.

[0367] In certain exemplary embodiments of the present invention,detector elements can be configured to perform optimally when impingedby x-rays traveling a straight path from the x-ray source to thedetector elements. Particularly, exemplary detector elements can includescintillation crystals that can generate light events when impinged byan x-ray beam. These light events can be output from each detectorelement and can be directed to photoelectrically responsive materials inorder to produce an electrical signal representative of the attenuatedbeam radiation received at the detector element. The light events can beoutput to photomultipliers or photodiodes that can produce individualanalog outputs. Exemplary detector elements can output a strong signalin response to impact by a straight path x-ray beam.

[0368] Without a collimator, X-rays can scatter when passing through theobject being imaged. Particularly, the object can cause some, but notall, x-rays to deviate from the straight path between the x-ray sourceand the detector. Therefore, detector elements can be impinged by x-raybeams at varying angles. System performance can be degraded whendetector elements are impinged by these scattered x-rays. When adetector element is subjected to multiple x-rays at varying angles, thescintillation crystal can generate multiple light events. The lightevents corresponding to the scattered x-rays can generate noise in thescintillation crystal output, and thus can cause artifacts in theresulting image of the object.

[0369] To, for example, reduce the effects of scattered x-rays, scattercollimators can be disposed between the object of interest and thedetector array. Such collimators can be constructed of x-ray absorbentmaterial and can be positioned so that scattered x-rays aresubstantially absorbed before impinging upon the detector array. Suchscatter collimators can be properly aligned with both the x-ray sourceand the detector elements so that substantially only straight pathx-rays impinge on the detector elements. Also, such scatter collimatorscan shield from x-ray radiation damage certain detector elements thatcan be sensitive at certain locations, such as the detector elementedges.

[0370] Certain exemplary embodiments of a scatter collimator of thepresent invention can include a plurality of substantially parallelattenuating blades and a plurality of substantially parallel attenuatingwires located within a housing. In certain exemplary embodiments, theattenuating blades, and thus the openings between adjacent attenuatingblades, can be oriented substantially on a radial line emanating fromthe x-ray source. That is, each blade and opening can be focallyaligned. The blades also can be radially aligned with the x-ray source.That is, each blade can be equidistant from the x-ray source. Scatteredx-rays, that is, x-rays diverted from radial lines, can be attenuated bythe blades. The attenuating wires can be oriented substantiallyperpendicular to the blades. The wires and blades thus can form atwo-dimensional shielding grid for attenuating scattered x-rays andshielding the detector array.

[0371] At least one embodiment of the invention can include a featurethat provides any of at least 5 functions: 1) separation of thecollimator by a predetermined distance from an array of radiationdetection elements; 2) alignment of the collimator to the array ofradiation detection elements (or vice versa); 3) attachment of thecollimator to the array of radiation detection elements; 4) attach thecollimator to a gantry or other detector sub-assembly; and/or 5) alignthe collimator to a gantry or other detector sub-assembly.

[0372] As an illustrative example, one embodiment of such a featurecould resemble “stilts” that can be formed independently or integrallyto a collimator and that can separate the collimator by a predetermineddistance from an array of radiation detection elements. In anotherembodiment, one or more of the stilts could serve as an alignment pin toalign the collimator with the array of radiation detection elements. Inanother embodiment, one or more of the stilts could include and/orinterface with an attachment mechanism to attach the collimator to thearray of radiation detection elements. For example, an end of a stiltcould slide into, via an interference fit, a socket of the array ofradiation detection elements. As example, a stilt could include ahemispherical protrusion that snaps into a corresponding hemisphericalindentation in a socket of the array of radiation detection elements.

[0373] As another illustrative example, one embodiment of such a featurecould invert the description of the previous paragraph by providing“holes” in the collimator that interface with “stilts” attached to orintegral with the radiation detection elements.

[0374] As yet another illustrative example, an embodiment of the featurecould be manifested in a collimator having an array of through-holes,each having a square cross-section. At one end of all or certainthrough-holes could be the feature, such as a groove that extends arounda perimeter of the square through-hole. A radiation detection elementcould have a square outer perimeter that includes a lip havingcorresponding dimensions to the groove that allows the radiationdetection element to snap into the through-hole of the collimator via aninterference fit, thereby fixing the position of the radiation detectionelement with respect to the collimator, aligning the radiation detectionelement with the collimator, and attaching the radiation detectionelement to the collimator.

[0375] Moreover, a modular collection of radiation detection elements,potentially cast according to an embodiment of the present invention,could attach to a collimator via one or more attachment features, any ofwhich could be formed independently of, or integrally with, either theradiation detection module and/or the collimator.

[0376] Depending on the embodiment, the scatter collimator can includeblades and wires, open air cells, and/or encapsulated cells. Certainexemplary embodiments can be fabricated as a true cross grid havingsepta in both radial and axial directions. The cross-grid structure canbe aligned in the radial and axial directions or it can be rotated.Thus, the cross grid can be aligned in two orthogonal directions.

[0377] Depending on the grid design, it might not be practical and/orpossible to remove the mold from the cast grid because of its shape orsize, e.g., if very thin septa or severe undercuts are involved. In suchcases, a material with a low x-ray absorptivity can be used for the moldand the final grid can be left encapsulated within the mold. Materialsused for encapsulation can include, but are not limited to,polyurethanes, acrylics, foam, plastics etc.

[0378] Because certain exemplary embodiments of the present inventioncan utilize photolithography in creating the laminated mold, greatflexibility can be possible in designing the shape of the open cells.Thus, round, square, hexagonal, and/or other shapes can be incorporated.Furthermore, the cells do not all need to be identical (a “redundantpattern”). Instead, they can vary in size, shape, and/or location(“non-redundant” pattern) as desired by the designer. In addition,because of the precision stack lamination of individual layers that canbe employed in fabricating the master, the cell shapes can vary in thethird dimension, potentially resulting in focused, tapered, and/or othershaped sidewalls going through the cell.

[0379] Because the cell shape can vary in the third dimension (i.e.going through the cell), the septa wall shape can also vary. Forexample, the septa can have straight, tapered, focused, bulging, and/orother possible shapes. Furthermore, the septa do not all need to beidentical (a “redundant pattern”). Instead, they can vary incross-sectional shape (“non-redundant” pattern) as desired by thedesigner.

[0380] Certain exemplary embodiments of the present invention canprovide a collimator or section of a collimator as a single cast piece,which can be inherently stronger than either a laminated structure or anassembly of precisely machined individual pieces. Such a cast collimatorcan be designed to withstand any mechanical damage from the significantg-forces involved in the gantry structure that can rotate as fast as 4revolutions per second. Furthermore, such a cast structure can besubstantially physically stable with respect to the alignment betweencollimator cells and detector elements.

[0381] Some exemplary embodiments of the present invention can provide acollimator or section of a collimator as a single cast collimator inwhich cells and/or cell walls can be focused in the radial direction,and/or in which cells and/or cells walls can be accurately aligned inthe axial direction.

[0382] Conversely, certain exemplary embodiments of the presentinvention can provide a collimator or section of a collimator as asingle cast collimator in which cells and/or cell walls can be focused(by stacking layers having slightly offset openings) in the axialdirection, and/or in which cells and/or cells walls can be curved (andfocused) in the radial direction.

[0383] Exemplary embodiments of the present invention can utilize any ofa wide number of different materials to fabricate the scattercollimator. A specific application can result in any of the followingmaterials being most appropriate, depending on, for example, the netdensity and the cell and septa size requirements. Lead or lead alloyalone can offer a density of 9-11 grams per cc;

[0384] Lead alloy can be loaded with a dense composite (e.g., tungsten,tantalum, and/or gold, etc.) powder to form a composite having a densityof 12-15 grams per cc;

[0385] Polymer can be loaded with a dense composite (e.g., lead,tungsten, tantalum, and/or gold, etc.) powder to form a composite havinga density of 8-9 grams per cc;

[0386] The cast grid made of lead alloy or any of the above combinationscan be encapsulated in a low density polymer such that the transmissionis minimally affected but scatter is significantly reduced.

[0387] In addition, certain embodiments of the present invention can beemployed to fabricate grids and/or collimators for which the mold can bepre-loaded with dense powder, followed by alloy or polymer.Alternatively, polymer or alloy can be pre-loaded with dense powder theninjected into the mold. In certain embodiments, the casting can beremoved from a flexible mold. In other embodiments, the mold can bedissolved or consumed to de-mold the casting. In certain embodiments, amaster can be removed layer-by-layer from rigid mold. Alternatively, thelost wax approach can be used in which the model is dissolvable wax,dissolvable PMMA, dissolvable polyurethane, dissolvable high-resolutionceramic, and/or some other dissolvable material.

[0388] The above description and examples have covered a number ofaspects of certain exemplary embodiments of the invention including, forexample, cell size and shape, different materials and densities, planarand non-planar orientations, and focused and unfocused collimators.

[0389] Additional Embodiments—Nuclear Medicine (SPECT) Collimator andDetector Array

[0390] In conventional X-ray or CT examinations, the radiation isemitted by a machine and then passes through the patient's body. Innuclear medicine exams, however, a radioactive material is introducedinto the patient's body (by injection, inhalation or swallowing), and isthen detected by a machine, such as a gamma camera or a scintillationcamera.

[0391] The camera can have a detector and means to compute the detectedimage. The detector can have at least one a scintillator crystal, whichtypically is planar. The scintillator can absorb the gamma radioactiveradiation, and emit a luminous scintillation in response, which can bedetected by an array of photomultiplier tubes of the detector. Thecomputation means can determine the coordinates of a locus ofinteraction of the gamma rays in the scintillator, which can reveal theprojected image of the body.

[0392] Because the radiation source in the patient can emit radiationomnidirectionally, a collimator can be located between the body and thescintillator. This collimator can prevent the transmission of thoseradioactive rays that are not propagating in a chosen direction.

[0393] Certain embodiments of the present invention can be used tofabricate structures useful for nuclear medicine. For example,collimators used in nuclear medicine, including pinhole, parallel-hole,diverging, and converging collimators, can be fabricated according toone or more exemplary methods of the present invention.

[0394] As another example, exemplary methods of the present inventioncan be used to fabricate high precision, high attenuation collimatorswith design flexibility for hole-format, which can improve theperformance of pixelated gamma detectors.

[0395] Certain exemplary embodiments of certain casting techniques ofthe present invention can be applied to the fabrication of othercomponents in detector systems. FIG. 47 is an assembly view ofcomponents of a typical pixelated gamma camera. Embodiments of certaincasting techniques of the present invention can be used to producecollimator 47010, scintillator crystals segmentation structure 47020,and optical interface 47030 between scintillator array (not visible) andphoto-multiplier tubes 47040.

[0396] In an exemplary embodiment, collimator 47010 can be fabricatedfrom lead, scintillator crystals segmentation structure 47020 can befabricated from a ceramic, and optical interface 47030 can be fabricatedfrom acrylic.

[0397] In certain exemplary embodiments, through the use of a commonfabrication process, two or more of these components can be made to thesame precision and/or positional accuracy. Moreover, two or more ofthese components can be designed to optimize and/or manage seams and/ordead spaces between elements, thereby potentially improving detectorefficiency for a given choice of spatial resolution. For example, in apixelated camera with non-matched detector and collimator, if thedetector's open area fraction (the fraction of the detector surface thatis made up of converter rather than inter-converter gap) is 0.75, andthe collimator's open area fraction (the fraction of the collimatorsurface that is hole rather than septum) is 0.75, the overall open areafraction is approximately (0.75)=0.56. For a similar camera in which thecollimator holes are directly aligned with the pixel converters, theopen area fraction is 0.75, giving a 33% increase in detectionefficiency without reduction in spatial resolution.

[0398] Certain embodiments of the present invention can provide parallelhole collimators and/or collimators having non-parallel holes, such asfan beam, cone beam, and/or slant hole collimators. Because certainembodiments of the present invention use photolithography in creatingthe master, flexibility is possible in designing the shape, spacing,and/or location of the open cells. For example, round, square,hexagonal, or other shapes can be incorporated. In addition, becausecertain embodiments of the present invention use precision stacklamination of individual layers to fabricate a laminated mold, the cellshapes can vary in the third dimension, resulting in focused, tapered,and/or other shaped sidewalls going through the cell. Furthermore, thecells do not all need to be identical (“redundant”). Instead, they canvary in size, shape or location (“non-redundant”) as desired by thedesigner, which in some circumstances can compensate for edge effects.Also, because a flexible mold can be used with certain embodiments ofthe present invention, collimators having non-planar surfaces can befabricated. In some cases, both surfaces are non-planar. However,certain embodiments of the present invention also allow one or moresurfaces to be planar and others non-planar if desired.

[0399] Certain embodiments of the present invention can fabricate acollimator, or section of a collimator, as a single cast piece, whichcan make the collimator less susceptible to mechanical damage, morestructurally stable, and/or allow more accurate alignment of thecollimator with the detector.

[0400] Certain embodiments of the present invention can utilize any of anumber of different materials to fabricate a collimator or othercomponent of an imaging system. A specific application could result inany of the following materials being chosen, depending, in the case of acollimator, on the net density and the cell and septa size requirements:

[0401] Lead or lead alloy alone can offer a density of 9-11 grams per cc

[0402] Polymer can be loaded with tungsten powder to form a compositehaving a density comparable to lead or lead alloys

[0403] Polymer can also be combined with other dense powder compositessuch as tantalum or gold to yield a density comparable to lead or leadalloys

[0404] Polymer can be combined with two or more dense powders to form acomposite having a density comparable to lead or lead alloys

[0405] Lead alloy can be loaded with tungsten powder to form a compositehaving a density of 12-15 grams per cc

[0406] Lead alloy can be loaded with another dense composites (tantalum,gold, other) to form a composite having a density of 12-15 grams per cc

[0407] Lead alloy can be combined with two or more dense powders to formcomposites having a density of 12-15 grams per cc (atomic number andattenuation)

[0408] The cast grid made of lead alloy or any of the above combinationscan be encapsulated in a low-density material such that the transmissionis minimally affected but scatter is reduced.

[0409] Thus, depending on the specific application, certain embodimentsof the present invention can create any of a wide range of densities forthe cast parts. For example, by adding tungsten (or other very densepowders) to lead alloys, net densities greater than that of lead can beachieved. In certain situations, the use of dense particles can providehigh “z” properties (a measure of radiation absorption). For certainembodiments of the present invention, as radiation absorption improves,finer septa walls can be made, which can increase imaging resolutionand/or efficiency.

[0410] In addition, certain embodiments of the present invention can beemployed to fabricate grids and/or collimators for which the mold can bepre-loaded with dense powder, followed by alloy or polymer.Alternatively, polymer or alloy can be pre-loaded with dense powder theninjected into the mold. In certain embodiments, the casting can beremoved from a flexible mold. In other embodiments, the mold can bedissolved or consumed to de-mold the casting. In certain embodiments, amaster can be removed layer-by-layer from rigid mold. Alternatively, thelost wax approach can be used in which the model is dissolvable wax,dissolvable PMMA, dissolvable polyurethane, dissolvable high-resolutionceramic, and/or some other dissolvable material.

[0411] With certain embodiments of the present invention, thestack-laminated master does not need to embody the net density of thefinal grid. Instead, it can have approximately the same mechanical shapeand size. Similarly, the final grid can be cast from relatively low costmaterials such as lead alloys or polymers. Furthermore, these finalgrids can be loaded with tungsten or other dense powders. As discussedpreviously, using certain embodiments of the invention, multiple moldscan be made from a single master and multiple grids can be cast at atime, if desired. Such an approach can lead to consistency of dimensionsand/or geometries of the molds and/or grids.

[0412] Because of the inherent precision of the lithographic process,certain embodiments of the present invention can prevent and/or minimizeassembly build up error, including error buildup across the surface ofthe grid and/or assembly buildup error as can occur in collimators inwhich each grid is individually assembled from photo-etched layers. Inaddition, process errors can be compensated for in designing thelaminated mold.

Example 6 Lead Collimator for Gamma Camera (Nuclear MedicineApplication)

[0413] Step 1: Creating the laminated mold: In this exemplary process,0.05 mm thick copper foils were chemically etched and then laminatedtogether using a metal-to-metal brazing process, for producing alaminated mold. Photo-masks were configured with a 2.0×2.0 millimetersquare open cell, with a 0.170 mm septal wall separating the cells. Thecells were arrayed having 10 rows and 10 columns, with a 2 mm borderaround the cell array. Photo-masks were produced to the samespecifications, by the same vendor as those described in example 1, step1.

[0414] The layers were designed so that the cell placement was identicalfrom layer to layer, which when assembled, produced a parallelcross-sectional shape. FIG. 42A is a top view of an x-ray grid 42000having an array of cells 42002 separated by septal walls 42004. FIG. 42Bis a cross-sectional view of x-ray grid 42000 taken along section lines42-42 of FIG. 42B showing that the placement of cells 42002 can also bedissimilar from layer to layer 42010-42050, so that when assembled,cells 42002 are focused specifically to a point source 42060 at a knowndistance from x-ray grid 42000.

[0415] The total number of layers in the stack lamination defined thethickness of the casting mold and final cast grid. The final thicknessof the lamination was specified at 0.118 inches, which required 57layers of copper foil, leaving a total thickness amount of 0.00007inches between each layer for a braze material. The layers wereprocessed by Tech Etch of Plymouth Mass., using standard photo-etchingtechniques and were etched in such a way that the cross-sectional shapeof the etched walls were perpendicular to the top and bottom surfaces ofthe foil (commonly referred to as straight sidewalls).

[0416] The method chosen to bond the grid layers together was ametal-to-metal brazing technique described earlier in detail as one oftwo exemplary methods of bonding layers together (eutectic braze alloy).The brazed lamination was then electro-plated with a coating of hardnickel, also described earlier.

[0417] Step 2: Creating a derived mold: An RTV mold was made from thestack laminated mold from step 1. Silastic® M RTV Silicone Rubber waschosen as the base material for the derived mold. This particularmaterial was used to demonstrate the resolution capability, releaseproperties, multiple castings, and dimensional repeatability of thederived mold from the laminated mold. Silastic M has the hardestdurometer of the Silastic® family of mold making materials. The derivedmold was configured as an open face mold.

[0418] The fixture used to create the derived casting mold is shown inFIG. 32 and was comprised of a precision machined aluminum ring 32010,precision ground glass plates 32020 and 32030, rubber gaskets 32040 and32050, and the laminated mold 32060. The base of the fixture 32020 was a5 inch square of 1 inch thick Plexiglas. On the top surface of thePlexiglas base was a 1″ thick, 3 inch diameter glass substrate 32030.The base and the glass substrate were separated by a {fraction (1/16)}inch thick, 4.5 inch diameter rubber gasket 32040. An additional 3.0inch rubber gasket 32050 was placed on the top surface of the glasssubstrate 32030. The rubber gaskets helped prevent unwanted flashing ofmolten material when casting. The laminated mold 32060 was placed on thetop gasket.

[0419] The shape and thickness of the glass created the entrance areawhere the casting material was poured into the mold. The material formedin this cavity was referred to as a controlled backing. It served as arelease aid for the final casting, and could later be removed from thecasting in a final machining process. A precision machined aluminum ring32010 having a 4.5 inch outside diameter and a 4 inch inside diameterwas placed over the master subassembly and interfaced with the lower 4.5inch diameter rubber gasket.

[0420] As illustrated in FIG. 32, the height of the ring was configuredso that the distance from the top surface of the master to the top ofthe ring was twice the distance from the base of the fixture to the topof the laminated mold. The additional height allowed the RTV material torise up during the degassing process. The ring portion of the fixtureassembly was used to locate the pouring of the mold material into theassembly, captivate the material during the curing process, and providean air escape while the mold material was degassed using vacuum. Thefixture was configured in such a way that all sides surrounding thelaminated mold were equal and common, in order to limit the effects orstresses put on the lamination from the mold material.

[0421] The Silastic® M RTV Silicone Rubber used for the mold fabricationwas prepared in accordance with the manufacturer's recommendations,using the process described earlier in example 1, step 2.

[0422] The laminated mold was characterized, before and after themold-making process, by measuring the average pitch distance of thecells, the septal wall widths, overall distance of the open grid area,and the finished thickness of the part. These dimensions were alsomeasured on the derived casting mold and compared with the laminatedmold before and after the mold-making process. The following chart liststhe dimensions of the lamination before and after the mold-making andthe same dimensions of the derived RTV mold. All dimensions were takenusing a Nikon MM-11 measuring scope at 200×magnification. Thesedimensions demonstrated the survivability of the master and thedimensional repeatability of the mold. Master Lamination RTV Mold MasterLamination Grid Feature (before mold-making) Silastic ® M (aftermold-making) Septal Wall Width 0.170 0.161 0.170 (mm) Cell Width (mm)2.000 × 2.000 2.010 × 2.010 2.000 × 2.000 Cell Pitch (mm) 2.170 × 2.1702.171 × 2.171 2.170 × 2.170 Pattern area (mm) 21.530 × 21.530 21.549 ×21.549 21.530 × 21.530 Thickness (mm) 2.862 2.833 2.862

[0423] Step 3: Casting the final collimator: A fine-featured leadcollimator was produced from the derived RTV silicone mold described instep 2. FIG. 43 is a side view of an assembly 43000 that includes anopen face mold 43010 that was used to produce a casting 43020 fromCERROBASE™ alloy. Casting 43020 was dimensionally measured and comparedto the laminated mold 43010. The backing 43030 of casting 43020 was 6millimeters in thickness and was removed using a machining process. GridFeatures Master Lamination Cast Collimator Septal Wall Width (mm) 0.1700.165 Cell Width (mm) 2.000 × 2.000 2.005 × 2.005 Cell Pitch (mm) 2.170× 2.170 2.170 × 2.170

[0424] The first step of the casting process was to pre-heat the derivedRTV mold to a temperature of 275 degrees F., which was 20 degrees abovethe melting point of the CERROBASE™ alloy. The mold was placed on aheated aluminum substrate, which maintained the mold at approximately275 degrees F. when it was placed in the vacuum bell jar.

[0425] In certain casting procedures, the material can be forced intothe mold in a rapid fashion, and cooled and removed quickly. In thiscase, the casting process was somewhat slowed in order to fully fill andevacuate the air from the complex cavity geometry of the mold. TheCERROBASE™ was then heated in an electric melting pot to a temperatureof 400 degrees F., which melted the alloy sufficiently above its meltpoint to remain molten during the casting process.

[0426] The next step was to pour the molten alloy into the mold, in sucha way as to aid in the displacement of any air in the cavity. This wasaccomplished by tilting the mold at a slight angle and beginning thepour at the lowest point in the cavity section of the mold. It was foundthat if the mold was placed in a flat orientation while pouring themolten alloy, significant amounts of air were trapped, creating problemsin the degassing phase of the process. Instead, once the mold wassufficiently filled with the molten alloy, the mold was slightlyvibrated or tapped in order to expel the largest pockets of air. Themold, on the heated aluminum substrate, was then placed in the vacuumbell jar, pumped down to atmosphere of 25-28 inches of mercury for 2minutes, which was sufficient time to evacuate any remaining airpockets. The mold was then removed from the vacuum bell jar andsubmersed in a quenching tank filled with water cooled to a temperatureof 50 degrees F. The rapid quench produced a fine crystalline grainstructure when the casting material solidified. The casting was thenremoved from the flexible mold by grasping the backing 43030, bymechanical means or by hand, and breaking the casting free of the moldusing an even rotational force, releasing the casting gradually from themold.

[0427] The final process step was removing the backing 43030 from theattached surface of the grid casting 43020 to the line shown in FIG. 43.Prior to removing the backing, the grid structure of the final casting43020 was filled or potted with a machinable wax, which provided thestructural integrity needed to machine the backing without distortingthe fine walls of the grid casting. The wax was sold under the productname MASTER™ Water Soluble Wax by the Kindt-Collins Corporation, ofCleveland, Ohio. The wax was melted at a temperature of 160-180 degreesF., and poured into the open cells of the cast grid. Using the sametechnique described above, the wax potted casting was placed in vacuumbell jar and air evacuated before being cooled. The wax was cooled toroom temperature and was then ready for the machining of the backing.

[0428] A conventional surface grinder was used to first rough cut thebacking from the lead alloy casting. The remaining casting was thenplaced on a lapping machine and lapped on the non-backing side of thecasting using a fine abrasive compound and lapping wheel. Thenon-backing side of the casting was lapped first so that the surface wasflat and parallel to within 0.010-0.015 millimeters to the adjacent castgrid cells. The rough-cut backing surface was then lapped using the sameabrasive wheel and compound so that it was flat and parallel to within0.100-0.015 millimeters of the non-backing side of the casting. Athickness of 2.750 millimeters was targeted as the final castingthickness. Upon completion of the lapping process, the casting wasplaced in an acid solution, comprised of 5% dilute HCl and water, withmild agitation until the wax was fully dissolved from the cells of thecasting.

[0429] In an alternative embodiment, individual castings could also bestacked, aligned, and/or bonded to achieve thicker, higher aspect ratiocollimators. Such collimators, potentially having a thicknesses measuredin centimeters, can be used in nuclear medicine.

Example 7 Non-Planar Collimator

[0430] A non-planar collimator can have several applications, such as,for example, in a CT environment. To create such an example of such acollimator, the following process was followed:

[0431] Step 1: Creating a laminated mold: For this example, a laminatedmold was designed and fabricated using the same process and vendorsdescribed in Example 1, step 1. The laminated mold was designed to serveas the basis for a derived non-planar casting mold. The laminated moldwas designed and fabricated with outside dimensions of 73.66 mm×46.66mm, a 5 mm border around a grid area having 52×18 open cell array. Thecells were 1 mm×1.980 mm separated by 0.203 septal walls.

[0432] The layers for the laminated mold were bonded using the sameprocess described in Example 1, step 1 (thermo-cured epoxy). Thedimensions of the laminated mold were specified to represent a typicalcollimator for CT x-ray scanning. Silastic® J RTV Silicone Rubber waschosen as a base material to create a derived non-planar casting moldbecause of its durometer which allowed it to more easily be formed intoa non-planar configuration. The laminated mold and fixture wasconfigured as an open face mold.

[0433] Step 2: Creating a derived non-planar mold: Silastic® J RTVSilicone Rubber was used for the derived mold fabrication and wasprepared in accordance with the manufacturers recommendations, using theprocess described earlier in example 1, step 2. FIG. 44 is a top view ofcasting assembly 44000. FIG. 45 is a side view of casting assembly44000.

[0434] The derived RTV mold 44010 was then formed into a non-planarconfiguration as shown in FIG. 45. The surface 44020 of casting fixturebase 44030 defined a 1-meter radius arc to which mold 44010 wasattached. A 1-meter radius was chosen because it is a common distancefrom the x-ray tube to the collimator in a CT scanner. Mold 44010 wasfastened to the convex surface 44020 of casting base 44030 with a hightemperature epoxy adhesive. A pour frame 44040 was placed around castingfixture base 44030. Pour frame 44040 had an open top to allow pouringthe casting material to a desired fill level and to allow evacuating theair from the casting material.

[0435] The laminated mold was characterized, before and after producingthe derived non-planar mold, by measuring the average pitch distance ofthe cells, the septal wall widths, overall distance of the open gridarea, and the finished thickness of the part. These dimensions were alsomeasured on the derived non-planar mold and compared with the masterbefore and after the mold-making process. The following chart lists thedimensions of the master lamination before and after the mold-making andthe same dimensions of the RTV mold in the planar state and curvedstate. All dimensions are in millimeters and were taken using a NikonMM-11 measuring scope at 200×magnification. Grid Master Lamination RTVMold (planar) RTV Mold (curved) Features (before mold-making) Silastic ®J Silastic ® J Septal Wall 0.203 0.183 0.193* Cell Width 1.980 × 1.0002.000 × 1.020 2.000 × 1.020 Cell Pitch 2.183 × 1.203 2.183 × 1.203 2.183× 1.213 Pattern area 39.091 × 62.353 39.111 × 62.373 39.111 × 62.883Thickness 7.620 7.544 7.544

[0436] Step 3: Casting a non-planar collimator: The derived non-planarRTV mold described in step 2, was used to create castings. Using thederived non-planar mold, the castings were produced from CERROBASE™alloy and were dimensionally measured and compared to the laminatedmold. Grid Features Master Lamination Cast Collimator Septal Wall Width(mm) 0.203 0.197 * Cell Width (mm) 1.000 × 1.980 1.006 × 1.986 CellPitch (mm) 1.203 × 2.183 1.203 × 2.183

[0437] The process used to fill the derived non-planar mold with thecasting alloy and the de-molding of the casting was the same processdescribed in Example 6.

[0438] The final process step included the removal of the backing fromthe grid casting. A wire EDM (electrode discharge machining) process wasfound to be the most effective way to remove the backing from thecasting, primarily due to the curved configuration of the casting. Thewire EDM process used an electrically charged wire to burn or cutthrough the casting material, while putting no physical forces on theparts. In this case, a fine 0.003 inch molybdenum wire was used to cutthe part, at a cutting speed of 1 linear inch per minute. This EDMconfiguration was chosen to limit the amount of recast material leftbehind on the cut surface of the part, leaving the finished septal wallswith a smooth surface finish. The casting was fixtured and orientated sothat the radial cutting of the backing was held parallel to the curvedsurface of the casting, which was a 1 meter radius.

Example 8 Mammography Scatter Reduction Grid

[0439] Another exemplary application of embodiments of the presentinvention is the fabrication of a mammography scatter reduction grid. Inthis example, a derived clear urethane mold for a fine-featured focusedgrid was made using a photo-etched stack lamination for the mastermodel. For making this mold, the master was designed and fabricatedusing the lamination process detailed in Example 7. A clear urethanecasting material was chosen as an example of a cast grid in which themold was left intact with the casting as an integral part of the gridstructure. This provided added strength and eliminated the need for afragile or angled casting to be removed from the mold.

[0440] Step 1: Creating a laminated mold: The laminated mold wasfabricated from photo-etched layers of copper. The mold was designed tohave a 63 mm outside diameter, a 5 mm border around the outside of thepart, and a focused 53 mm grid area. FIG. 46 is a top view of a gridarea 46000, which was comprised of hexagonal cells 46010 that were 0.445mm wide, separated by 0.038 mm septal walls 46020. The cells werefocused from the center of the grid pattern to a focal point of 60centimeters, similar to that shown in FIG. 42B. The grid was made from35 layers of 0.050 mm thick stainless steel, which when assembledcreated a 4:1 grid ratio. Each grid layer utilized a separate photo-maskin which the cells are arrayed out from the center of the grid patternat a slightly larger distance from layer to layer. This created thefocused geometry as shown in FIG. 42B. With this cell configuration, thefinal casting produced a hexagonal focused grid with a transmission ofabout 82%. The photo-masks and etched layers were produced using thesame vendors and processes described in example 1, step 1.

[0441] Step 2: Creating a derived urethane mold: Urethane mold materialwas chosen for its high-resolution, low shrink factor, and low density.Because of its low density, the urethane is somewhat transparent to thetransmission of x-rays. The mold material, properties, and processparameters were as described earlier in example 4, step 4.

[0442] The fixture used to create the derived urethane casting mold wasthe same as that described in Example 6, step 2.

[0443] Before assembling the mold fixture, the laminated mold wassprayed with a mold release, Stoner E236. The fixture was assembled asshown in FIG. 32 and heated to 125 degrees F. Then it was filled withthe Water Clear urethane and processed using the same parametersdescribed in example 4, step 4. The laminated mold was characterized,before and after making the derived mold, by measuring the average pitchdistance of the cells, the septal wall widths, overall distance of theopen grid area, and the finished thickness of the lamination. Thesedimensions were also measured on the derived urethane casting mold andcompared with the lamination before and after the mold-making process.The following chart lists the dimensions of the lamination before andafter the mold-making and the same dimensions of the urethane mold. Alldimensions were in millimeters and were taken using a Nikon MM-11measuring scope at 200×magnification. Urethane Casting Master LaminationSystem Master Lamination Grid Features (before mold-making) Water Clear(after mold-making) Septal Wall Width  0.038  0.037  0.038 Cell Width 0.445 (hexagonal)  0.446 (hexagonal)  0.445 (hexagonal) Cell Pitch 0.483  0.483  0.483 Pattern area (mm2) 53.000 52.735 53.000 Thickness 1.750  1.729  1.750

[0444] Step 3: Casting the anti-scatter grid: A focused scatterreduction grid was produced by casting a lead alloy, CERROLOW-117™ alloyinto the derived urethane mold described in step 2. The backingthickness of the casting was 2 millimeters and was removed using asurface grinding process.

[0445] The first step of the process was to pre-heat the derivedurethane mold to a temperature of 137 degrees F., which was 20 degreesabove the 117 degree melting point of the CERROLOW™ alloy. The mold wasplaced on a heated aluminum substrate, which maintained the mold toapproximately 117 degrees F. when it was placed in the vacuum bell jar.The CERROLOW™ was then heated in an electric melting pot to atemperature of 120 degrees F., which melted the alloy sufficiently abovethe melt point of the material, keeping the material molten during thecasting process. The process steps for filling the mold were the same asthose described in Example 6, step 3.

[0446] The CERROLOW™ alloy was chosen for casting because of its highresolution capability, low melting point, and relatively high density.The urethane mold was left remaining to provide structural integrity forthe fine lead alloy features. The urethane is also somewhat transparentto x-rays because of its low density (1 g/cm3) compared to the castingalloy.

Example 9 Collimator with Tungsten Loaded Alloy (Variation of Example 6)

[0447] Additional collimator samples have been produced using the sameprocess described in Example 6 above, with the exception of the castingalloy and that it was loaded with tungsten powder prior to the castingprocess. The tungsten powder (KMP115) was purchased through the KuliteTungsten Corporation of East Rutherford, N.J. CERROLOW™ alloy was loadedto raise the net density of the alloy from a density of 9.16 grams percubic centimeter to 13 grams per cubic centimeter.

[0448] In certain radiological applications, elimination of secondaryscattered radiation, also known as Compton scatter, and shielding can bean objective. The base density of the CERROLOW™ alloy can be sufficienton its own to absorb the scattered radiation, but the presence of thetungsten particles in the septal walls can increase the density andimprove the scatter reduction performance of the part. The casting wasdimensionally measured and compared to the laminated mold used to createthe derived RTV mold. Grid Features Master Lamination Cast CollimatorMaterial Copper CERROLOW-117 Plus Tungsten Powder Density (g/cc) 8.9612.50 Septal Wall Width 0.038  0.036 Cell Width 0.445 (hexagonal)  0.447(hexagonal) Cell Pitch 0.483  0.483

[0449] Prior to casting, the tungsten powder was loaded or mixed intothe CERROLOW™ alloy. The first step was to super-heat the alloy to 2-3times its melting point temperature (between 234-351 degrees F.), and tomaintain this temperature. The tungsten powder, having particle sizesranging from 1-15 microns in size, was measured by weight to 50% of thebase alloy weight in a furnace crucible. A resin-based, lead-compatiblesoldering flux was added to the tungsten powder to serve as a wettingagent when combining the powder and the alloy. The resin flux wasobtained from the Indium Corporation of America of Utica N. Y., underthe name Indalloy Flux # 5RMA.

[0450] The flux and the powder were heated to a temperature of 200degrees F. and mixed together after the flux became liquid. The heatedCERROLOW™ alloy and the fluxed powder then were combined and mixed usinga high-shear mixer at a constant temperature of 220 degrees F. The netdensity of the alloy loaded with the powder was measured at 12.5 gramsper cubic centimeter. The loaded alloy was molded into the derived RTVmold, and finished machined using the same process described in Example6.

Example 10 Collimator Structure Cast from a Ceramic (Variation ofExample 7)

[0451] This example demonstrates a structure that could be co-alignedwith a cast collimator. The structure could be filled with detectormaterials, such as a scintillator, for pixilation purposes. Ceramic waschosen for high temperature processing of the scintillator materials,which are normally crystals.

[0452] Additional cast samples have been produced using a castablesilica ceramic material using the same mold described in Example 7above. The ceramic material, Rescor™-750, was obtained from theCotronics Corporation of Brooklyn, N. Y. The ceramic material wasprepared prior to casting per the manufacturer's instructions. Thisincluded mixing the ceramic powder with the supplied activator. Per themanufacturer's instructions, an additional 2% of activator was used toreduce the viscosity of the mixed casting ceramic, in order to aid infilling the fine cavity features of the mold.

[0453] The mold was filled and degassed using a similar process and thesame mold and non-planar fixture as Example 7 above, covered with a thinsheet of plastic, and allowed to cure for 16 hours at room temperature.The ceramic casting then was removed from the RTV mold and post cured toa temperature of 1750 degrees F., heated at a rate of 200 degrees F. perhour. Post-curing increased the strength of the cast grid structure. Theceramic casting then was ready for the final grinding and lappingprocess for the removal of the backing. Additional Fields of Use

[0454] Additional exemplary fields of use, illustrative functionalitiesand/or technology areas, and representative cast devices arecontemplated for various embodiments of the invention, as partiallylisted below. Note that any such device, and many others notspecifically listed, can utilize any aspect of any embodiment of theinvention as disclosed herein to provide any of the functionalities inany of the fields of use. For example, in the automotive industry,inertial measurement can be provided by an accelerometer, at least acomponent of which that has been fabricated according to a method of thepresent invention. Likewise, in the telecommunications field, one ormore components of an optical switch, and possibly an entire opticalswitch, can be fabricated according to a method of the presentinvention.

[0455] Embodiments of such devices can provide any of a number offunctionalities, including, for example, material, mechanical, thermal,fluidic, electrical, magnetic, optical, informational, physical,chemical, biological, and/or biochemical, etc. functionalities.Embodiments of such devices can at least in part rely on any of a numberof phenomena, effects, and/or properties, including, for example,electrical, capacitance, inductance, resistance, piezoresistance,piezoelectric, electrostatic, electrokinetic, electrochemistry,electromagnetic, magnetic, hysteresis, signal propagation, chemical,hydrophilic, hydrophobic, Marangoni, phase change, heat transfer,fluidic, fluid mechanical, multiphase flow, free surface flow, surfacetension, optical, optoelectronic, electro-optical, photonic, wave optic,diffusion, scattering, interference, diffraction, reflection,refraction, absorption, adsorption, mass transport, momentum transport,energy transport, species transport, mechanical, structural dynamic,dynamic, kinematic, vibration, damping, tribology, material, bimetallic,shape memory, biological, biochemical, cell transport, electrophoretic,physical, Newtonian, non-Newtonian, linear, non-linear, and/or quantum,etc. phenomena, effects, and/or properties.

[0456] Moreover, note that unless stated otherwise, any device, discretedevice component, and/or integrated device component fabricatedaccording to any method disclosed herein can have any dimension,dimensional ratio, geometric shape, configuration, feature, attribute,material of construction, functionality, and/or property disclosedherein.

[0457] Among the many contemplated industries and/or fields of use are:

[0458] Aerospace

[0459] Automotive

[0460] Avionics

[0461] Biotechnology

[0462] Chemical

[0463] Computer

[0464] Consumer Products

[0465] Defense

[0466] Electronics

[0467] Manufacturing

[0468] Medical devices

[0469] Medicine

[0470] Military

[0471] Optics

[0472] Pharmaceuticals

[0473] Process

[0474] Security

[0475] Telecommunications

[0476] Transportation

[0477] Among the many contemplated technology areas are:

[0478] Acoustics Active structures and surfaces

[0479] Adaptive optics

[0480] Analytical instrumentation

[0481] Angiography

[0482] Arming and/or fusing

[0483] Bio-computing

[0484] Bio-filtration

[0485] Biomedical imaging

[0486] Biomedical sensors

[0487] Biomedical technologies

[0488] Cardiac and vascular technologies

[0489] Catheter based technologies

[0490] Chemical analysis

[0491] Chemical processing

[0492] Chemical testing

[0493] Communications

[0494] Computed tomography

[0495] Computer hardware

[0496] Control systems

[0497] Data storage

[0498] Display technologies

[0499] Distributed control

[0500] Distributed sensing

[0501] DNA assays

[0502] Electrical hardware

[0503] Electronics

[0504] Fastener mechanisms

[0505] Fluid dynamics

[0506] Fluidics

[0507] Fluoroscopy

[0508] Genomics

[0509] Imaging

[0510] Inertial measurement

[0511] Information technologies

[0512] Instrumentation

[0513] Interventional radiography

[0514] Ion source technologies

[0515] Lab-on-a-chip

[0516] Measurements

[0517] Mechanical technologies

[0518] Medical technologies

[0519] Microbiology

[0520] Micro-fluidics

[0521] Micro-scale power generation

[0522] Non-invasive surgical devices

[0523] Optics

[0524] Orthopedics

[0525] Power generation

[0526] Pressure measurement

[0527] Printing

[0528] Propulsion

[0529] Proteomics

[0530] Radiography

[0531] RF (radio frequency) technologies

[0532] Safety systems

[0533] Satellite technologies

[0534] Security technologies

[0535] Signal analysis

[0536] Signal detection

[0537] Signal processing

[0538] Surgery

[0539] Telecommunications

[0540] Testing

[0541] Tissue engineering

[0542] Turbomachinery

[0543] Weapon safeing

[0544] Among the many contemplated cast devices and/or cast devicecomponents are at least one:

[0545] accelerometer

[0546] actuator

[0547] airway

[0548] amplifier

[0549] antenna

[0550] aperture

[0551] application specific microinstrument

[0552] atomizer

[0553] balloon catheter

[0554] balloon cuff

[0555] beam

[0556] beam splitter

[0557] bearing

[0558] bioelectronic component

[0559] bio-filter

[0560] biosensor

[0561] bistable microfluidic amplifier

[0562] blade passage

[0563] blower

[0564] bubble

[0565] capacitive sensor

[0566] capacitor

[0567] cell sorting membrane

[0568] chain

[0569] channel

[0570] chromatograph

[0571] clip

[0572] clutch

[0573] coextrusion

[0574] coil

[0575] collimator

[0576] comb

[0577] comb drive

[0578] combustor

[0579] compression bar

[0580] compressor

[0581] conductor

[0582] cooler

[0583] corrosion sensor

[0584] current regulator

[0585] density sensor

[0586] detector array

[0587] diaphragm

[0588] diffractive grating

[0589] diffractive lens

[0590] diffractive phase plate

[0591] diffractor

[0592] diffuser

[0593] disc

[0594] display

[0595] disposable sensor

[0596] distillation column

[0597] drainage tube

[0598] dynamic value

[0599] ear plug

[0600] electric generator

[0601] electrode array

[0602] electronic component socket

[0603] electrosurgical hand piece

[0604] electrosurgical tubing

[0605] exciter

[0606] fan

[0607] fastener

[0608] feeding device

[0609] filter

[0610] filtration membrane

[0611] flow passage

[0612] flow regulator

[0613] fluid coextrusion

[0614] fluidic amplifier

[0615] fluidic oscillator

[0616] fluidic rectifier

[0617] fluidic switch

[0618] foil

[0619] fuel cell

[0620] fuel processor

[0621] fuse

[0622] gear

[0623] grating

[0624] grating light valve

[0625] gyroscope

[0626] hearing aid

[0627] heat exchanger

[0628] heater

[0629] high reflection coating

[0630] housing

[0631] humidity sensor

[0632] impeller

[0633] inducer

[0634] inductor

[0635] infra-red radiation sensor

[0636] infusion sleeve

[0637] infusion test chamber

[0638] interferometer

[0639] introducer sheath

[0640] introducer tip

[0641] ion beam grid

[0642] ion deposition device

[0643] ion etching device

[0644] jet

[0645] joint

[0646] lens

[0647] lens array

[0648] lenslet

[0649] link

[0650] lock

[0651] lumen

[0652] manifold

[0653] mass exchanger

[0654] mass sensor

[0655] membrane

[0656] microbubble

[0657] microchannel plate

[0658] microcombustor

[0659] microlens

[0660] micromirror

[0661] micromirror display

[0662] microprism

[0663] microrelay

[0664] microsatellite component

[0665] microshutter

[0666] microthruster

[0667] microtiterplate

[0668] microturbine

[0669] microwell

[0670] mirror

[0671] mirror display

[0672] mixer

[0673] multiplexer

[0674] nozzle

[0675] optical attenuator

[0676] optical collimator

[0677] optical switch

[0678] ordinance control device

[0679] ordinance guidance device

[0680] orifice

[0681] phase shifter

[0682] photonic switch

[0683] pin array

[0684] plunger

[0685] polarizer

[0686] port

[0687] power regulator

[0688] pressure regulator

[0689] pressure sensor

[0690] printer head

[0691] printer head component

[0692] prism

[0693] processor

[0694] processor socket

[0695] propeller

[0696] pump

[0697] radiopaque marker

[0698] radiopaque target

[0699] rate sensor

[0700] reaction chamber

[0701] reaction well

[0702] reactor

[0703] receiver

[0704] reflector

[0705] refractor

[0706] regulator

[0707] relay

[0708] resistor

[0709] resonator

[0710] RF switch

[0711] rim

[0712] safe-arm device

[0713] satellite component

[0714] scatter grid

[0715] seal

[0716] septum

[0717] shroud

[0718] shunt

[0719] shutter

[0720] spectrometer

[0721] stent

[0722] stopper

[0723] supercharger

[0724] switch

[0725] tank

[0726] temperature regulator

[0727] temperature sensor

[0728] thruster

[0729] tissue scaffolding

[0730] titerplate

[0731] transmission component

[0732] transmitter

[0733] tunable laser

[0734] turbine

[0735] turbocharger

[0736] ultra-sound transducer

[0737] valve

[0738] vane

[0739] vessel

[0740] vibration sensor

[0741] viscosity sensor

[0742] voltage regulator

[0743] waveplate

[0744] well

[0745] wheel

[0746] wire coextrusion

[0747] Additional detailed examples of some of the many possibleembodiments of devices and/or device components that can be fabricatedaccording to a method of the present invention are now provided.Additional potential embodiments of these and/or other contemplateddevices and/or device components are described in U.S. Patent and/orPatent Application Nos. US2001/0031531, US2001/0034114, 408,677,460,377, 1,164,987, 3,379,812, 3,829,536, 4,288,697, 4,356,400,4,465,540, 4,748,328, 4,801,379, 4,812,236, 4,825,646, 4,856,043,4,951,305, 5,002,889, 5,043,043, 5,147,761, 5,150,183, 5,190,637,5,206,983, 5,252,881, 5,378,583, 5,447,068, 5,450,751, 5,459,320,5,483,387, 5,551,904, 5,576,147, 5,606,589, 5,620,854, 5,638,212,5,644,177, 5,681,661, 5,692,507, 5,702,384, 5,718,618, 5,721,687,5,729,585, 5,763,318, 5,773,116, 5,778,468, 5,786,597, 5,795,748,5,814,235, 5,814,807, 5,836,150, 5,849,229, 5,851,897, 5,924,277,5,929,446, 5,932,940, 5,949,850, 5,955,801, 5,955,818, 5,962,949,5,963,788, 5,985,204, 5,994,801, 5,994,816, 5,998,260, 6,004,500,6,011,265, 6,014,419, 6,018,422, 6,018,680, 6,055,899, 6,068,684,6,075,840, 6,084,626, 6,088,102, 6,124,663, 6,133,670, 6,134,294,6,149,160, 6,152,181, 6,155,634, 6,175,615, 6,185,278, 6,188,743,6,197,180, 6,210,644, 6,219,015, 6,226,120, 6,226,120, 6,242,163,6,245,487, 6,245,849, 6,250,070, 6,252,938, 6,261,066, 6,276,313,6,280,090, 6,299,300, 6,307,815, 6,310,419, 6,314,887, 6,318,069,6,318,849, 6,324,748, 6,328,903, 6,333,584, 6,333,584, 6,336,318,6,338,199, 6,338,249, 6,340,222, 6,344,392, 6,346,030, 6,350,983,6,360,424, 6363712,6363843, 6,367,911, 6,373,158, 6,375,871, 6,381,846,6,382,588, 6,386,015, 6,387,713, 6,392,187, 6,392,313, 6,392,524,6,393,685, 6,396,677, 6,397,677, 6,397,793, 6,398,490, 6,404,942,6,408,884, 6,409,072, 6,410,213, 6,415,860, 6,416,168, 6,433,657,6,440,284, 6,445,840, 6,447,727, 6,450,047, 6,453,083, 6,454,945,6,458,263, 6,462,858, 6,467,138, 6,468,039, 6,471,471, and/or 6480320,each of which are incorporated by reference herein in their entirety.

[0748] MicrovalvesMicrovalves can be enabling components of manymicrofluidic systems that can be used in many industry segments.Microvalves are generally classified as passive or active valves, butcan share similar flow characteristics through varied orificegeometries. Diaphragm microvalves can be useful in many fluidicapplications. FIG. 48A is a top view of an array 48010 of genericmicrodevices 48000. FIG. 48B is a cross section of a particularmicrodevice 48000 in this instance a diaphragm microvalve, taken alongsection lines 48-48 of FIG. 48A, the microvalve including diaphragm48010 and valve seat 48020, as shown in the open position. FIG. 49 is across section of the diaphragm microvalve 48000, again taken alongsection lines 48-48 of FIG. 48A, the microvalve in the closed position.

[0749] The flow rate through diaphragm microvalve 48000 can becontrolled via the geometric design of the valve seat, which is oftenreferred to as gap resistance. The physical characteristics of the valveseat, in combination with the diaphragm, can affect flow characteristicssuch as fluid pressure drop, inlet and outlet pressure, flow rate,and/or valve leakage. For example, the length, width, and/or height ofthe valve seat can be proportional to the pressure drop across themicrovalve's diaphragm. Additionally, physical characteristics of thediaphragm can influence performance parameters such as fluid flow rate,which can increase significantly with a decrease in the Young's modulusof the diaphragm material. Valve leakage also can become optimized witha decrease in the Young's modulus of the diaphragm, which can enablehigher deflection forces, further optimizing the valve's overallperformance and/or lifetime.

[0750] Typical microvalve features and specifications can include avalve seat: The valve seat, which is sometimes referred to as the valvechamber, can be defined by its size and the material from which it ismade. Using an exemplary embodiment of a method of the presentinvention, the dimensions of the chamber can be as small as about 10microns by about 10 microns if square, about 10 microns in diameter ifround, etc., with a depth in the range of about 5 microns to millimetersor greater. Thus, aspect ratios of 50, 100, or 200:1 can be achieved.The inner walls of the chamber can have additional micro features and/orsurfaces which can influence various parameters, such as flowresistance, Reynolds number, mixing capability, heat exchange foulingfactor, thermal and/or electrical conductivity, etc.

[0751] The chamber material can be selected for application specificuses. As examples, a ceramic material can be used for high temperaturegas flow, or a chemical resistant polymer can be used for chemical uses,and/or a bio-compatible polymer can be used for biological uses, to namea few. Valve chambers can be arrayed over an area to create multi-valveconfigurations. Each valve chamber can have complex inlet and outletchannels and/or ports to further optimize functionality and/or provideadditional functionality.

[0752] Typical microvalve features and specifications can also include adiaphragm: The diaphragm can be defined by its size, shape, thickness,durometer (Young's modulus), and/or the material from which it is made.Using an exemplary embodiment of a method of the present invention, thedimensions of the diaphragm can be as small as about 25 microns by about25 microns if square, about 25 microns in diameter if round, etc., withthickness of about 1 micron or greater. The surface of one side or bothsides of the diaphragm could have micro features and/or surfaces toinfluence specific parameters, such as diaphragm deflection and/or flowcharacteristics. The diaphragm can be fabricated as a free form devicethat is attached to the valve in a secondary operation, and/or attachedto a substrate. Diaphragms can be arrayed to accurately align to amatching array of valve chambers.

[0753] Potential performance parameters can include valve seat anddiaphragm material, diaphragm deflection distance, inlet pressure, flow,and/or lifetime.

[0754] Micropumps

[0755]FIGS. 50 and 51 are cross-sectional views of a particularmicro-device 48000, in this case a typical simplified micropump, takenalong section lines 48-48 of FIG. 48A. Micropumps can be an enablingcomponent of many microfluidic systems that can be used in many industrysegments. Reciprocating diaphragm pumps are a common pump type used inmicro-fluidic systems. Micropump 50000 includes two microvalves 50010and 50020, a pump cavity 50030, valve diaphragms 50040 and 50050, andactuator diaphragm 50060.

[0756] At the initial state of pump 50000, the actuation is off, bothinlet and outlet valves 50010 and 50020 are closed, and there is nofluid flow through pump 50000. Once actuator diaphragm 50060 is movedupwards, the cavity volume will be expanded causing the inside pressureto decrease, which opens inlet valve 50010 and allows the fluid to flowinto and fill pump cavity 50030, as seen in FIG. 50. Then actuatordiaphragm 50060 moves downward, shrinking pump cavity 50030, whichincreases the pressure inside cavity 50030. This pressure opens outletvalve 50020 and the fluid flows out of the pump cavity 50030 as seen inFIG. 51. By repeating the above steps, continuous fluid flow can beachieved. The actuator diaphragm can be driven using any of variousdrives, including pneumatic, hydraulic, mechanical, magnetic,electrical, and/or piezoelectrical, etc. drives.

[0757] Typical microvalve features and specifications can include any ofthe following, each of which are similar to those features andspecifications described herein under Microvalves:

[0758] Valve seats

[0759] Valve actuators (diaphragm)

[0760] Cavity chamber

[0761] Actuator diaphragm

[0762] Potential performance parameters can include valve seat, chambermaterial, actuator diaphragm material, valve diaphragm material,deflection distance for actuator, deflection distance for valvediaphragms, inlet pressure, outlet pressure, chamber capacity, flowrate, actuator drive characteristics (pulse width, frequency, and/orpower consumption, etc.), and/or lifetime.

[0763] Microwells and Microwell Arrays

[0764] Microwells can be an enabling component in many devices used formicro-electronics, micro-mechanics, micro-optics, and/or micro-fluidicsystems. Precise arrays of micro-wells, potentially having hundreds tothousands of wells, can further advance functionality and processcapabilities. Microwell technology can be applied to DNA micro-arrays,protein micro-arrays, drug delivery chips, microwell detectors, gasproportional counters, and/or arterial stents, etc. Fields of use caninclude drug discovery, genetics, proteomics, medical devices, x-raycrystallography, medical imaging, and/or bio-detection, to name a few.

[0765] For example, using exemplary embodiments of the presentinvention, microwells can be engineered in the third (Z) dimension toproduce complex undercuts, pockets, and/or sub-cavities. Wells can alsobe arrayed over various size areas as redundant or non-redundant arrays.These features can include the dimensional accuracies and/or tolerancesdescribed earlier. Also, a range of surface treatments within the wellstructure are possible that can enhance the functionality of the well.

[0766] Examples of Microwell Applications:

[0767] DNA Microarrays: Scientists can rely on DNA microarrays forseveral purposes, including 1) to determine gene identification,presence, and/or sequence in genotype applications by comparing the DNAon a chip; 2) to assess expression and/or activity level of genes;and/or 3) to measure levels of proteins in protein based arrays, whichcan be similar to DNA arrays.

[0768] DNA microarrays can track tens of thousands of reactions inparallel on a single chip or array. Such tracking is possible becauseeach probe (a gene or shorter sequence of code) can be deposited in anassigned position within the cell array. A DNA solution, representing aDNA sample that has been chopped into constituent sequences of code, canbe poured over the entire array (DNA or RNA). If any sequence of thesample matches a sequence of any probe, the two will bind, andnon-binding sequences can be washed away. Because each sequence in thesample or each probe can be tagged or labeled with a fluorescent, anybound sequences will remain in the cell array and can be detected by ascanner. Once an array has been scanned, a computer program can convertthe raw data into a color-coded readout.

[0769] Protein Microarrays: The design of a protein array is similar tothat of a DNA chip. Hundreds to thousand of fluorescently labeledproteins can be placed in specific wells on a chip. The proteins can bedeposited on the array via a pin or array of pins that are designed todraw fluidic material from a well and deposit it on the inside of thewell of the array. The position and configuration of the cells on thearray, the pins, and the wells are located with the accuracy needed touse high-speed pick-and-place robotics to move and align the chip overthe fluidic wells. A blood sample is applied to the loaded array andscanned for bio-fluorescent reactions using a scanner.

[0770] Certain embodiments of the invention enable DNA or Proteinmicroarrays having a potentially large number of complex 3-dimensionalwells to be fabricated using any of a range of materials. For example,structures can be fabricated that combine two or more types of materialin a microwell or array. Additional functionality and enhancements canbe designed into a chip having an array of microwells. Wells can beproduced having cavities capable of capturing accurate amounts of fluidsand/or high surface-to-volume ratios. Entrance and/or exitconfigurations can enhance fluid deposition and/or provide visualenhancements to scanners when detecting fluorescence reactions. Veryprecise well locations can enable the use of pick and place roboticswhen translating chips over arrays of fluidic wells. Certain embodimentsof the invention can include highly engineered pins and/or pin arraysthat can be accurately co-aligned to well arrays on chips and/or canhave features capable of efficiently capturing and/or depositing fluidsin the wells.

[0771] Arterial Stents: Stents are small slotted cylindrical metal tubesthat can be implanted by surgeons to prevent arterial walls fromcollapsing after surgery. Typical stents have diameters in the 2 to 4millimeter range so as to fit inside an artery. After insertion of astent, a large number of patients experience restenosis a narrowing ofthe artery—because of the build-up of excess cells around the stent aspart of the healing process. To minimize restenosis, techniques areemerging involving the use of radioactive elements or controlled-releasechemicals that can be contained within the inner or outer walls of thestent.

[0772] Certain embodiments of the invention can provide complex3-dimensional features that can be designed and fabricated into theinside, outside, and/or through surfaces of tubing or other generallycylindrical and/or contoured surfaces. Examples 4 and 5 teach such afabrication technique for a 3 mm tube. Certain embodiments of theinvention can allow the manufacture of complex 2-dimensional and/or3-dimensional features through the wall of a stent. Micro surfaces andfeatures can also be incorporated into the stent design. For example,microwells could be used to contain pharmaceutical materials. The wellscould be arrayed in redundant configurations or otherwise. The stentfeatures do not have to be machined into the stent surface one at atime, but can be applied essentially simultaneously. From a qualitycontrol perspective, features formed individually typically must be 100%inspected, whereas features produced in a batch typically do not.Furthermore, a variety of application specific materials (e.g.,radio-opaque, biocompatible, biosorbable, biodissolvable, shape-memory)can be employed.

[0773] Microwell Detectors: Microwells and microwell arrays can be usedin gas proportional counters of various kinds, such as for example, inx-ray crystallography, in certain astrophysical applications, and/or inmedical imaging. One form of microwell detector consists of acylindrical hole formed in a dielectric material and having a cathodesurrounding the top opening and anode at the bottom of the well. Otherforms can employ a point or pin anode centered in the well. Themicrowell detector can be filled with a gas such as Xenon and a voltagecan be applied between the cathode and anode to create a relativelystrong electric field. Because of the electric field, each x-raystriking an atom of the gas can initiate a chain reaction resulting inan “avalanche” of hundreds or thousands of electrons, thereby producinga signal that can be detected. This is known as a gas electronmultiplier. Individual microwell detectors may be used to detect thepresence and energy level of x-rays, and if arrays of microwelldetectors are employed, an image of the x-ray source can be formed. Sucharrays can be configured as 2-dimensional and/or 3-dimensional arrays.

[0774] Certain embodiments of the invention can enable arrays of complex3-dimensional wells to be fabricated and bonded or coupled to otherstructures such as a cathode material and anode material. It is alsopossible to alter the surface condition of the vertical walls of thewells, which can enhance the laminar flow of electrons in the well. Anumber of possible materials can be used to best meet the needs of aparticular application, enhancing parameters such as conductivity,die-electrical constant, and/or density. Certain embodiments of theinvention can further enable the hybridizing of micro-electronics to awell array, in particular because of accurate co-alignment between themicro-electronic feature(s), and/or the structural elements of the well.

[0775] Typical Microwell Features, Specifications and PotentialPerformance Parameters:

[0776]FIG. 52 is a top view of an exemplary microwell array 52000,showing microwells 52010, and the X- and Y-axes. Array 52000 is shown asrectangle, but could be produced as a square, circle, or any othershape. Either of the array's dimensions as measured along the X-orY-axes can range from 20 microns to 90 centimeters. Microwells 52010 areshown having circular perimeters, but could also be squares, rectangles,or any other shape. Array 52000 is shown having a redundant array ofwells 52010, but could be produced to have non-redundant wells. Thepositional accuracy of wells 52010 can be accurate to the specificationsdescribed herein for producing lithographic masks. Wells can range insize from 0.5 microns to millimeters, with cross-sectionalconfigurations as described herein.

[0777] Using certain embodiments of a method of the present invention,certain materials can be used to produce microwell arrays for specificuses. For example, a ceramic material can be used for high-temperaturegas flow, a chemical resistant polymer can be used for chemical uses,and/or a bio-compatible polymer can be used for biological uses, to namea few. Specialty composite materials can enhance application specificfunctionality by being conductive, magnetic, flexible, hydrophilic,hydrophobic, piezoelectric, to name a few.

[0778] Using an embodiment of a method of the present invention,microwells with certain 3-dimensional cross-sectional shapes can beproduced. FIG. 52 is a top view of an exemplary array 52000 ofmicrowells 52010.

[0779]FIG. 53 is a cross-sectional view, taken at section lines 52-52 ofFIG. 52, of an exemplary microwell 53000 having an entrance 53010.Entrance 53010 is shown having a tapered angle, which could be angledfrom 0 degrees to nearly 180 degrees. Entrance 53010 is also shownhaving a different surface than well area 53020. Well area 53020 can besquare, round, rectangular, or any other shape. Well area 53020 canrange in size from 0.5 microns to millimeters in width and can bedimensionally controlled in the Z-axis to have aspect ratios of fromabout 50:1 to about 100:1.

[0780]FIG. 54 is a cross-sectional view, taken at section lines 52-52 ofFIG. 52, of an alternative exemplary microwell 54000 that defines anentrance 54010, a well 54020, and an exit 54030. Microwell 54000 can beused in applications that require fluids that are conveyed from below orabove the entrance 54010 and/or exit 54030, and deposited in well 54020.Using an embodiment of a method of the present invention, microwell54000 can be produced so that well 54020 is hydrophilic and entrance54010 and exit 54030 are hydrophobic to, for example, enable thedeposition of fluid into well 54020, and discourage the fluiddeposition, retention, and/or accumulation on entrance 54010, on exit54030, and/or on the chip's surface. For uses where microelectroniccontrols or chips are employed, the material surrounding and/or definingentrance 54010 and/or 54030 can be conductive or non-conductive, asrequired. Well 54020 can be dimensioned to accurately contain apre-determined amount of fluid.

[0781] The shape and size of corner feature 54040 can be defined toencourage the discharge of a fluid material from a fluidic channel on apin, when a pin is produced using any of certain embodiments of theinvention. For example, pins can be produced having fluidic channels orundercuts that are positioned radially at the end of the pin. Theundercuts can serve as reservoirs that increase surface area-to-volumeratios and/or hold accurate amounts of fluids. If the undercuts aredesigned to be relatively flexible and larger than the opening dimensionat feature 54040, fluid can be squeezed from the reservoir as the fluidpasses by corner feature 54040. Entrance 54010 can have an angle thatpromotes the visibility of a material, such as a fluid, in well 54020.The material surrounding and/or defining well 54020 can be fabricated tohave micro-surface features to increase the well's surfacearea-to-volume ratio.

[0782]FIG. 55 is a top view of an exemplary microwell 55000 showing awell area 55010 and sub-cavities 55020. FIG. 56 is a cross-sectionalview, taken at section lines 56-56 of FIG. 55, of microwell 55000showing well 55010 and sub-cavities 55020. Well 55010 can extend throughthe material that defines it, as shown in FIG. 56, or can be a closedwell having a solid floor. Sub-cavities 55020 can be incorporated withina well to, for example, increase an area of the surface(s) bordering thewell, a volume, and/or surface area-to-volume ratio of the well.Sub-cavities 55020 can be continuous rings as shown in FIG. 55.Alternatively, sub-cavities 55020 can be discrete pockets formingsub-wells within well 55010. Sub-cavities 55020 can be positioned on ahorizontal floor or subfloor of well 55010 as shown in FIG. 55, on thevertical walls of well 55010, and/or on another surface. Sub-cavities55020 can have circular, square, rectangular, and/or any of a variety ofother cross-sectional shapes. Sub-cavities 55020 can also be positionedto provide an enhanced visual perspective of a deposited material fromwhich could be angled from 0 degrees to nearly 180 degrees, such as anapproximately perpendicular angle, so as to enhance scanning performanceor resolution.

[0783] Filtration

[0784] Filtration can be an important element in many industriesincluding medical products, food and beverage, pharmaceutical andbiological, dairy, waste water treatment, chemical processing, textile,and/or water treatment, to name a few. Filters are generally classifiedin terms of the particle size that they can separate. Micro-filtrationgenerally refers to separation of particles in the range ofapproximately 0.01 microns through 20 microns. Separation of largerparticles than approximately 10-20 microns is typically referred to asparticle separation. There are two common forms of filtration,cross-flow and dead-end. In cross-flow separation, a fluid stream runsparallel to a membrane of a filter while in dead-end separation, thefilter is perpendicular to the fluid flow. There are a very large numberof different shapes, sizes, and materials used for filtration dependingon the particular application.

[0785] Certain embodiments of the invention can be filters suitable formicro-filtration and/or particle filtration applications. Certainembodiments of the invention allow fabrication of complex 2-dimensionaland/or 3-dimensional filters offering redundant or non-redundant poresize, shape, and/or configuration. For example, a circular filter canhave an array of redundant generally circular through-features, eachthrough-feature having a diameter slightly smaller than a targetparticle size. Moreover, the through-feature can have a tapered,countersunk, and/or undercut entrance, thereby better trapping anytarget particle that encounters the through-feature. Further, thecylindrical walls defined by the through-feature can have channelsdefined therein that are designed to allow a continued and/orpredetermined amount of fluid flow around a particle once the particleencounters the through-feature. The fluid flow around the particle cancreate eddys vortices, and/or other flow patterns that better trap theparticle against the filter.

[0786] Certain embodiments of the filter can have features that allowthe capture of particles of various sizes at various levels of thefilter. For example, an outer layer of the filter can capture largerparticles, a middle layer can capture mid-sized particles, and a finallayer can capture smaller particles. There are numerous techniques foraccomplishing such particle segregation, including providingthrough-features having tapered, stepped, and/or diminishingcross-sectional areas.

[0787] In certain embodiments, the filter can include means fordetecting a pressure drop across the filter, and/or across anyparticular area, layer, and/or level of the filter. For example, in afilter designed to filter a gas such as air, micro pitot tubes can befabricated into each layer of the filter (or into selected layers of thefilter). Such pressure measurement devices can be used to determine thepressure drop across each layer, to detect the level of “clogging” ofthat layer, and/or to determine what size and/or concentration ofparticles are entrapped in the filter.

[0788] Further, certain embodiments of the invention allow forfabrication of filters in a wide range of materials including metals,polymers, plastics, ceramics, and/or composites thereof. In biomedicalapplications, for instance, a biocompatible material can be used thatwill allow filtration of blood or other body fluids. Using certainembodiments of the invention, filtration schemes can be engineered asplanar or non-planar configurations.

[0789] Sorting

[0790] Sorting can be considered a special type of filtration in whichparticles, solids, and/or solids are separated by size. In biomedicalapplications for example, it may be desirable to sort blood or othertypes of cells by size and deliver different sizes to differentlocations. Certain embodiments of the invention can enable thefabrication of complex 3-dimensional structures that allow cells to besorted by size (potentially in a manner similar to that discussed hereinfor filters) and/or for cells of different sizes to be delivered throughdifferent size micro-channels or between complex 3-dimensionalstructures. Structures can be material specific and on planar ornon-planar surfaces.

[0791] Membranes

[0792] Membranes can offer filtration via pore sizes ranging fromnanometers to a few microns in size. Membrane filtration can be used forparticles in the ionic and molecular range, such as for reverse osmosisprocesses to desalinate water. Membranes are generally fabricated ofpolymers, metals, or ceramics. Micro-filtration membranes can be dividedinto two broad types based on their pore structure. Membranes havingcapillary-type pores are called screen membranes, and those havingso-called tortuous-type pores are called depth membranes.

[0793] Screen membranes can have nearly perfectly round pores that canbe dispersed randomly over the outer surface of the membrane. Screenmembranes are generally fabricated using a nuclear track and etchprocess. Depth membranes offer a relatively rough surface where thereappear to be openings larger than the rated size pore, however, thefluid must follow a random tortuous path deeper into the membrane toachieve their pore-size rating. Depth membranes can be fabricated ofsilver, various cellulosic compounds, nylon, and/or polymeric compounds.

[0794] Certain embodiments of the invention enable fabrication ofmembranes having complex 3-dimensional shapes, sizes, and/orconfigurations made of polymers, plastics, metals, and/or ceramics, etc.Furthermore, such membranes can embody redundant or non-redundant pores,and can be fabricated to be flexible, rigid, and/or non-planar dependingupon the material and/or application requirements.

[0795] Heaters

[0796] Certain exemplary embodiments of the present invention canprovide heaters and/or components thereof, potentially having highresolution and/or high aspect ratios. For example, an exemplaryembodiment of the present invention can provide a resistive heaterhaving numerous wire, strip, and/or coil, etc. elements havingsubstantially large length and/or width dimensions with respect to theirthickness dimensions. Certain exemplary embodiments of the presentinvention can provide heaters that utilize a Seebeck effect for heating.

[0797] Heat Exchangers

[0798] Certain exemplary embodiments of the present invention canprovide heat exchangers and/or components thereof, potentially havinghigh resolution and/or high aspect ratios. For example, an exemplaryembodiment of the present invention can provide a heat exchanger havingnumerous “fins” or other surfaces having substantially large lengthand/or width dimensions with respect to their thickness dimensions,thereby providing relatively large surface area to volume ratios tofacilitate heat transfer. Such heat exchangers can be used for heatingand/or cooling of a target fluid and/or material. Also, exemplaryembodiments of the present invention can provide thin-walled tubularheat exchangers, having tubes that potentially incorporate “fins” and/orother heat transfer surfaces. Exemplary embodiments of fins and the likecan have secondary features that can be useful for further increasingsurface area, manipulating and/or optimizing flow, controlling fouling,etc. Certain exemplary embodiments of the present invention can provideheat exchangers that utilize a Peltier, Seebeck, and/or Joule effect forcooling and/or heating.

[0799] Mass Exchangers

[0800] Certain exemplary embodiments of the present invention canprovide mass exchangers and/or components thereof, potentially havinghigh resolution and/or high aspect ratios. For example, an exemplaryembodiment of the present invention can provide a mass exchanger havingnumerous “fins” or other surfaces capable of releasing an impregnatedand/or bound material, and/or having receptors for receiving a targetmaterial. Each such fin can have substantially large length and/or widthdimensions with respect to their thickness dimensions, thereby providingrelatively large surface area to volume ratios to facilitate masstransfer. Another exemplary embodiment can provide a mass exchanger,such as pieces of packing, each having numerous surfaces and having alarge surface area to volume ratio. Another exemplary embodiment canprovide a mass exchanger, such as a static mixer having numerous fluiddividing/mixing surfaces. Exemplary embodiments of fins and the like canhave secondary features that can be useful for further increasingsurface area, manipulating and/or optimizing mass transfer, etc.

[0801] Surface Reactors

[0802] Certain exemplary embodiments of the present invention canprovide surface reactors and/or components thereof, potentially havinghigh resolution and/or high aspect ratios. For example, an exemplaryembodiment of the present invention can provide a surface reactor havingnumerous “fins” or other surfaces comprising and/or bound to a materialcapable of reacting with a target material, and/or catalyzing such areaction. Each such fin can have substantially large length and/or widthdimensions with respect to their thickness dimensions, thereby providingrelatively large surface area to volume ratios to facilitate higherreaction rates. Exemplary embodiments of fins and the like can havesecondary features that can be useful for further increasing surfacearea, manipulating and/or optimizing reaction rates, controllingheating, cooling, mixing, and/or flow, etc.

[0803] Fuel Cells

[0804] Certain exemplary embodiments of the present invention canprovide a fuel cell having one or more discrete and/or integratedcomponents such as a channel, manifold, separator, pump, valve, filter,heater, cooler, heat exchanger, mass exchanger, and/or surface reactor,etc., of any size and/or configuration. Such a fuel cell can be usefulas a power cell, battery, charger, etc. For example, an embodiment ofthe invention can provide a fuel cell having a solid electrolytedisposed between an oxygen electrode and a fuel electrode, and one ormore separators can contact the surface of one of the electrodesopposite of the electrolyte. At least one electrode of the cell candefine a micro-channel pattern, wherein the micro-channel cross-sectioncan be varied, such that reactant gas flowing through the micro channelscan achieve tailored local flow, pressure, and/or velocitydistributions. An exemplary embodiment of the invention can provide aproton exchange diffusion membrane fuel cell having a membrane and/orchannels. An exemplary embodiment of the invention can provide a fluidfuel cell, such as a hydrogen fuel cell, proton exchange member, and/ora direct methanol fuel cell, utilizing one or more fluid mixers, mixingchambers, pumps, and/or recirculators.

[0805] Turbomachinery and Machinery

[0806] Certain exemplary embodiments of the present invention canprovide turbomachinery devices and/or components thereof, potentiallyhaving high resolution and/or high aspect ratios. For example, anexemplary embodiment can provide a microturbine having an impeller,rotor, blades, stages, seals, and/or nozzles, etc., any of which canhigh a high aspect ratio be formed from a material having a highstrength, and/or be formed from a material having desired thermalperformance capabilities, such as a ceramic. The microturbine can thatcan be coupled to a microgenerator for generating electrical powerand/or can be used for generating thrust. Another exemplary embodimentcan provide a microcombustion engine having free pistons magneticallycoupled to electromagnets for control and power transfer.

[0807] Ion Beam Technologies

[0808] Certain exemplary embodiments of the present invention canprovide ion beam devices and/or components thereof, potentially havinghigh resolution and/or high aspect ratios. For example, spacepropulsion, surface cleaning, ion implantation, and high energyaccelerators use two or three closely spaced multiple-apertureelectrodes to extractions from a source and eject them in a collimatedbeam. The electrodes are called “grids” because they are perforated witha large number of small holes in a regular array. A series of gridsconstitute an “ion optics” electrostatic ion accelerator and focusingsystem.

[0809] Ion Thrusters

[0810] On-board propulsion systems can be used to realize a variety ofspacecraft maneuvers. In satellites, for example, these maneuversinclude the processes of orbit raising (e.g., raising from a low Earthorbit to a geostationary orbit), stationkeeping (e.g., correcting theinclination, drift and eccentricity of a satellite's orbit) and attitudecontrol (e.g., correcting attitude errors about a satellite's roll,pitch and yaw axes).

[0811] Certain exemplary embodiments of the present invention canprovide propulsion and/or micropropulsion devices and/or componentspotentially having high resolution and/or high aspect ratios. Forexample, an exemplary embodiment can provide an ion thruster,microthruster, Kaufman-type ion engine, and/or electric rocket enginethat can be useful for maintaining the orbit and/or relative position ofa geosynchronous satellite. Such a device can utilize an orifice,orifice array, and/or grid. In certain embodiments, an ion thruster gridcan have a spherically-formed and/or domed screen pattern with, forexample, a high resolution and/or high aspect ratio.

[0812] Ion beam sources designed for spacecraft propulsion, that is, ionthrusters, typically are preferred to have long lifetimes (10,000 hoursor more), be efficient, and be lightweight. Ion thrusters have beensuccessfully tested in space, and show promise for significant savingsin propellant because of their high specific impulse (an order ofmagnitude higher than that of chemical rocket engines). They have yet toachieve any significant space use, however, because of lifetimelimitations resulting from grid erosion and performance constraintsresulting from thermal-mechanical design considerations, particularlythe spacing of metallic grids, including molybdenum.

[0813] In an ion thruster, a plasma is created and confined within thebody of the thruster. Ions from the plasma are electrostaticallyaccelerated rearwardly by an ion-optics system. The reaction with thespacecraft drives it forwardly, in the opposite direction. The forceproduced by the ion thruster is relatively small. The ion thruster istherefore operated for a relatively long period of time to impart therequired momentum to the heavy spacecraft. For some missions the ionthruster must be operable and reliable for thousands of hours ofoperation, and with multiple starts and stops.

[0814] The ion-optics system can include grids to which appropriatevoltages are applied in order to accelerate the ions rearwardly. In atypical electron bombardment ion thruster, a cathode produces electronsthat strike neutral gas atoms introduced through a propellant feed line.The electrons ionize the gas propellant and produce a diffuse plasma. Ina radio frequency ion thruster, the propellant is ionizedelectromagnetically by an external coil, and there is no cathode. Inboth cases, an anode associated with the plasma raises its positivepotential. To maintain the positive potential of the anode, a powersupply pumps to ground potential some of the electrons that the anodecollects from the plasma. These electrons are ejected into space by aneutralizer to neutralize the ion beam. Magnets act to inhibit electronsand ions from leaving the plasma. Ions drift toward the ion optics, andenter the holes in a screen grid. A voltage difference between thescreen grid and an accelerator grid accelerates the ions, therebycreating thrust. The screen grid is at the plasma potential, and theaccelerator grid is held at a negative potential to prevent downstreamelectrons from entering the thruster. Optionally, the optics can includea decelerator grid located slightly downstream of the accelerator gridand held at ground potential or at a lesser negative potential than theaccelerator grid to improve beam focusing and reduce ion impingement onthe negative accelerator grid.

[0815] The grids can be in a facing orientation to each other, spacedapart by relatively small clearances such as about 0.035 inches at roomtemperature. The grids can include aligned apertures therethrough. Someof the ions accelerated by the applied voltages can pass through theapertures, providing the propulsion. Others of the ions can impact thegrids, heating them and etching away material from the grids by physicalsputtering. The heating and electrostatic forces on the grids cancombine to cause substantial mechanical forces at elevated temperatureon the grids, which can distort the grids unevenly. The unevendistortion of the grids can cause adjacent grids to physically approacheach other, rendering them less efficient and prone to shorting againsteach other. These effects can be taken into account in the design of thegrids and the operation of the ion thruster, so that the thruster canremain functional for the required extended lifetimes. However,limitations may be placed on the operation of the ion thruster becauseof grid distortion, such as a relatively slow ramp-up in power duringstartup and operation, so that the adjacent grids do not expand sodifferently that they come into contact.

[0816] A factor that can affect the efficiency and/or the weight of ionthrusters is how closely and precisely the grids can be positioned whilemaintaining relative uniformity in the grid-to-grid spacing at highoperating temperatures or in conditions where the spatial temperature isnonuniform and thermal distortion can occur because of temperaturegradients.

[0817] Grids are frequently made of molybdenum formed into a domedshape. The molybdenum can resist material removal by physicalsputtering. The domed shape can establish the direction of change due tothermal expansion and/or can aid in preventing a too-close approach ofthe adjacent grids as a result of differences in temperatures of theadjacent grids.

[0818] Exemplary embodiments of ion thruster grids of the presentinvention, such as those formed according to an exemplary embodiment ofa method of the present invention, can be precisely formed into matchingshapes, which can account for deformation that can occur due to thermalexpansion when a thruster heats in operation. Changes in the actualspacing and the uniformity of spacing over the grid surfaces between thegrids can potentially be predicted and/or controlled.

[0819] Exemplary embodiments of ion thruster grids of the presentinvention, such as those formed according to an exemplary embodiment ofa method of the present invention, can be formed of any moldablematerial, include tungsten, molybdenum, ceramics, graphite, etc.

[0820] Exemplary embodiments of ion thruster grids of the presentinvention, such as those formed according to an exemplary embodiment ofa method of the present invention, can have relatively long lifetimes,allow for precise alignment and/or spacing between grids, and/or allowfor precise alignment and/or spacing of grid openings.

[0821] Ion Beam Grids

[0822] Ion beams can be used in the production of components in themicro-electronics industry and magnetic thin film devices in the storagemedia industry. Typically, an ion beam, such as an argon ion beam, has alarge area, a high current and an energy of between 100 eV and 2 keV.The beam can be used in a number of ways to modify the surface of asubstrate, for example by sputter deposition, sputter etching, milling,or implantation.

[0823] In a typical ion beam source (or ion gun) a plasma is produced byadmitting a gas or vapor to a low pressure discharge chamber containinga heated cathode and an anode which serves to remove electrons from theplasma and to give a surplus of positively charged ions which passthrough a screen grid or grids into a target chamber which is pumped toa lower pressure than the discharge chamber. Ions are formed in thedischarge chamber by electron impact ionization and move within the bodyof the ion gun by random thermal motion. The plasma will thus exhibitpositive plasma potential which is higher than the potential of anysurface with which it comes into contact. Various arrangements of gridscan be used, the potentials of which are individually controlled. In amultigrid system, the first grid encountered by the ions is usuallypositively biased whilst the second grid is negatively biased. A furthergrid may be used to decelerate the ions emerging from the ion source soas to provide a collimated beam of ions having more or less uniformenergy. For ion sputtering a target is placed in the target chamberwhere this can be struck by the beam of ions, usually at an obliqueangle, and the substrate on to which material is to be sputtered isplaced in a position where sputtered material can impinge on it. Whensputter etching, milling or implantation is to be practiced thesubstrate is placed in the path of the ion beam.

[0824] Hence, in a typical ion gun an ion arriving at a multiapertureextraction grid assembly first meets a positively biased grid.Associated with the grid is a plasma sheath. Across this sheath isdropped the potential difference between the plasma and the grid. Thisaccelerating potential will attract ions in the sheath region to thefirst grid. Any ion moving through an aperture in this first grid, andentering the space between the first, positively biased grid, and thesecond, negatively biased, grid is strongly accelerated in an intenseelectrical field. As the ion passes through the aperture in the secondgrid and is in flight to the grounded target it is moving through adecelerating field. The ion then arrives at an grounded target with anenergy equal to the potential of the first, positive, grid plus thesheath potential.

[0825] Exemplary embodiments of ion beam grids of the present invention,such as those formed according to an exemplary embodiment of a method ofthe present invention, can have relatively long lifetimes, allow forprecise alignment and/or spacing between grids, and/or allow for precisealignment and/or spacing of grid openings. Such grids can be planarand/or non-planar, can have redundant and/or non-redundant gridopenings, can have anisotropic and/or isotropic grid openings, and/orcan be constructed of nearly any moldable material, including compositematerials.

[0826] Microfluidics

[0827] Certain exemplary embodiments of the present invention canprovide fluidic and/or microfluidic devices and/or components thereof,potentially having high resolution and/or high aspect ratios. Forexample, an exemplary embodiment can provide a pressure regulator and/orcontroller that utilizes a valve, orifice, and/or nozzle having a highaspect ratio and formed using an embodiment of the present invention.

[0828] Actuators

[0829] Certain exemplary embodiments of the present invention canprovide actuators and/or components thereof, potentially having highresolution and/or high aspect ratios. For example, an exemplaryembodiment can provide a valve actuator having an electromagnetic,magnetic, piezoelectric, electrostatic, bimetallic, and/or shape memorycomponent formed using an embodiment of the present invention and havinga high aspect ratio.

[0830] Attenuators

[0831] Certain exemplary embodiments of the present invention canprovide attenuators and/or components thereof, potentially having highresolution and/or high aspect ratios. For example, an exemplaryembodiment can provide an acoustical attenuator having numerousmicrobaffles for absorbing undesired sound waves, such as sound waves ofa particular frequency range. Such baffles can be textured, dimensioned,and/or shaped to enhance their performance capabilities. Likewise,attenuators can be provided for attenuating flow, electromagneticradiation (e.g., light, electrical current, x-rays, etc.), etc.

[0832] Motion Devices

[0833] Certain exemplary embodiments of the present invention canprovide gyroscopes, accelerometers, tilt detectors, etc., and/orcomponents thereof, potentially having high resolution and/or highaspect ratios. Such devices can be useful for navigation,stabilitization, airbag crash systems, vibration detection, earthquakedetection, anti-theft and/or security systems, active suspensions,automated braking systems, vehicle rollover prevention systems,headlight leveling systems, seatbelt tensioners, motor controllers,pedometers, stereo speakers, computer peripherials, flight simulators,sports training, robots, machine health monitors, etc. For example, anexemplary embodiment can provide an accelerometer having a cantileveredinertial mass coupled to at least one electrical element, such as acapacitive sensor that is adapted to generate a signal upon sufficientchange in acceleration (movement) of the cantilevered inertial mass. Incertain embodiments, the mass and electrical element can besubstantially co-planar. In certain embodiments, the mass can have asubstantial aspect ratio, and electrical elements can be provided inorthogonal and/or multiple planes, so that changes in orientation,displacement, and/or motion (e.g., linear, curvilinear, and/orrotational velocity, acceleration, jerk, pulse, etc.) in any directioncan be sensed, measured, and/or analyzed.

[0834] Mirrors

[0835] Certain exemplary embodiments of the present invention canprovide a mirror and/or components thereof, potentially having highresolution and/or high aspect ratios. Such a mirror can be a componentof an optical device and/or an opto-mechanical device, such as anopto-mechanical switching cell and/or a laser scanner, such as is usedin a bar-code scanner or a holographic data storage system. Exemplaryarrays of mirrors can be redundant and/or non-redundant. Exemplarymirrors can be planar and/or non-planar. Exemplary mirrors can have areflectivity that varies in any fashion (e.g., linearly, non-linearly,polarly, radially, controllably, periodically, thermally, etc.) across asurface of the mirror.

[0836] Grating Light Valves

[0837] Grating light valves can resemble small reflectors/diffractors,each comprising several structures that resemble ribbon-like beamssupported on each end, which can electrostatically actuated upwards ordownwards (typically a fraction of the wavelength of visible light). Theribbon-like structures can be arranged to form an element that variablyreflects or diffracts light, in either a continuous or discrete (on-off)manner.

[0838] Grating light valves can have utility in optical attenuators,switches, relays, direct-to-plate printers, HDTV monitors, electroniccinema projectors, and/or commercial flight simulator displays.

[0839] Exemplary embodiments of grating light valves of the presentinvention, such as those formed according to an exemplary embodiment ofa method of the present invention, can include redundant and/ornon-redundant arrays of reflector and/or diffractor elements. Each suchelement can be planar and/or non-planar, and can include an actuator,such as those used in optical switching arrays.

[0840] Fuses

[0841] Certain exemplary embodiments of the present invention canprovide methods for fabricating a fuse and/or components thereof,potentially having a high-resolution and/or high-aspect ratio, which canbe used for triggering and/or disconnecting the flow of fluid and/orcurrent. For example, fluid fuse comprising a low melting (fusible)alloy can be useful for triggering and/or actuating a sprinkler head ina fire protection system. As another example, an electrical fusecomprising an electrically fusible alloy can be useful for disconnectinga current flow to an electronic and/or electrical device.

[0842] Signal Detecting Collimators and Devices

[0843] Certain exemplary embodiments of the present invention canprovide methods for fabricating a grid structure and/or componentsthereof, potentially having a high-resolution and/or high-aspect ratio,which can be used for signal detection collimators. Such devices can beused in the field of acoustics to, for example, enhance acousticalsignal detection and/or analysis, by for example, reflecting,dispersing, filtering, and/or absorbing sound waves. Such devices can beused in the field of imaging to, for example, enhance image contrast andquality by refracting, diffracting, reflecting, dispersing, filtering,and/or absorbing scattered radiation (sometimes referred to as“off-axis” radiation and/or “secondary” radiation). In this context,“radiation” means electromagnetic radiation, and can include radio,television, microwave, infrared, visible light, ultraviolet, alpha-rays,beta-rays, gamma rays, and/or x-rays, etc., and can even include highenergy particles, ion beams, etc. Moreover, much of the followingdiscussion regarding radiation is analogous to acoustical energy,vibration, and/or other forms of energy that have a varying and/orfrequency component (e.g., a time-varying component, a spatially-varyingcomponent, a dimensionally-varying component, etc.).

[0844] As an example, certain exemplary embodiments of the presentinvention can provide a collimator having optical properties, such ascell walls capable of absorbing certain wavelengths, that can be used asa notch filter. Other such collimators can have certain cells filledwith a material that has certain refractive properties, therebyproviding a lens effect with those cells. Other such collimators canhave reflective and/or curved cell walls thereby serving as a reflectorand/or wave guide.

[0845] Certain exemplary embodiments of the present invention canprovide a collimator having at least one curved face, and possiblyhaving both faces curved, such that each cell is “pointed” in adifferent direction. In various embodiments, the curve can be circular,elliptical, curvilinear, cylindrical, and/or spherical, etc., and can beconcave and/or convex.

[0846] Such collimators can be useful for detecting a direction of aradiation source with respect to the collimator and/or the imagingmachine comprising the collimator, particularly when the machine alsocomprises a pixilated detector array and an image processing capability.

[0847] Thus, in certain embodiments, such as those in which the “outer”face of the collimator is convex, such collimators can function as aform of “wide-angle lens” for whatever type of radiation the collimatoris designed to pass. Moreover, by analyzing the time variance of thedetected radiation, such machines can determine changes in direction orintensity of the emitted and/or incoming radiation. Further, byanalyzing the frequency components of the detected radiation, suchmachines can determine, perhaps with a high degree of precision, thenature of the radiation source.

[0848] As an example, an imaging machine comprising such a curvedcollimator could be deployed at a location having a relatively wide viewof a stadium parking lot. The collimator can direct light originatingfrom any particular location in the view to a corresponding detectorelement. By virtue of its power, time, and/or frequency analysiscapability, such an imaging machine could detect the source of a brightand rapid flash of infrared and visible light and/or other forms ofradiation, such as occurs when a handgun is fired. The imaging machinecould then alert authorities to the location of the fired handgun, andcould trigger a video camera to turn to and zoom in on the location tocapture a visible image of the scene, potentially capturing images ofthe faces of witnesses and/or perpetrators, license plate numbers, etc.

[0849] As another example, an imaging machine comprising such a curvedcollimator could be deployed at a location having a relatively wide viewof a port, shipping channel, runway, rail yard, border crossing,roadway, warehouse, parking lot, etc. Once deployed, the imaging machinecan detect, for example, gamma radiation, such as emitted from aradioactive source, such as a radioactive medical waste, nuclear fuel,and/or a radiation bomb. Upon detection, the imaging machine could alertauthorities to the approach, movement, and/or specific location of theradioactive source.

[0850] As yet another example, an imaging machine comprising a concavecollimator could be deployed at a conveyor and opposite a radiationsource, such as is used for scanning passenger bags in commercialairports, train stations, bus depots, etc. In an environment with manysuch conveyors each having a radiation source, such a collimator canisolate radiation to that coming from its corresponding radiationsource.

[0851] Although the invention has been described with reference tospecific embodiments thereof, it will be understood that numerousvariations, modifications and additional embodiments are possible, andaccordingly, all such variations, modifications, and embodiments are tobe regarded as being within the spirit and scope of the invention. Also,references specifically identified and discussed herein are incorporatedby reference as if fully set forth herein.

What is claimed is:
 1. A device, comprising a cast collimator derivedfrom a metallic foil stack lamination mold, said collimator defining afeature adapted to contain a plurality of scintillators.
 2. The deviceof claim 1, wherein said collimator comprises a ceramic.
 3. A device,comprising a cast collimator derived from a metallic foil stacklamination mold, said collimator defining a feature adapted to contain aplurality of radiation detection elements.
 4. The device of claim 3,wherein said plurality of radiation detection elements are secured bysaid feature.
 5. A device, comprising a cast collimator derived from ametallic foil stack lamination mold, said collimator defining a crossgrid.
 6. A device, comprising a cast collimator derived from a metallicfoil derived stack lamination mold, said collimator adapted to absorbradiation scattered in two orthogonal directions.
 7. A device,comprising a cast collimator derived from a metallic foil stacklamination mold, said collimator adapted to shield a plurality ofradiation detectors from scattered radiation.
 8. A device, comprising acast collimator derived from a metallic foil stack lamination mold, saidcollimator adapted to shield a plurality of radiation reflectors fromscattered radiation.
 9. A device, comprising a cast component derivedfrom a metallic foil stack lamination mold, said component defining afeature having a dimension of less than 4 centimeters.
 10. A device,comprising a cast component derived from a metallic foil stacklamination mold, said component defining a feature having a dimension ofless than 3 centimeter.
 11. A device, comprising a cast componentderived from a metallic foil stack lamination mold, said componentdefining a feature having a dimension of less than 1 centimeters.
 12. Adevice, comprising a cast component derived from a metallic foil stacklamination mold, said component defining a feature having a dimension ofless than 1 centimeter.
 13. A device, comprising a cast componentderived from a metallic foil stack lamination mold, said componentdefining a feature having a dimension of less than 500 microns.
 14. Adevice, comprising a cast component derived from a metallic foil stacklamination mold, said component defining a feature having a dimension ofless than 250 microns.
 15. A device, comprising a cast component derivedfrom a metallic foil stack lamination mold, said component defining afeature having a dimension of less than 200 microns.
 16. A device,comprising a cast component derived from a metallic foil stacklamination mold, said component defining a feature having a dimension ofless than 150 microns.
 17. A device, comprising a cast component derivedfrom a metallic foil stack lamination mold, said component defining afeature having a dimension of less than 100 microns.
 18. A device,comprising a cast component derived from a metallic foil stacklamination mold, said component defining a feature having a dimension ofless than 50 microns.
 19. A device, comprising a cast component derivedfrom a metallic foil stack lamination mold, said component defining afeature having a dimension of less than 25 microns.
 20. A device,comprising a cast component derived from a metallic foil stacklamination mold, said component defining a feature having a dimension ofless than 20 microns.
 21. A device, comprising a cast component derivedfrom a metallic foil stack lamination mold, said component defining afeature having a dimension of less than 15 microns.
 22. A device,comprising a cast component derived from a metallic foil stacklamination mold, said component defining a feature having a dimension ofbetween approximately 4 centimeters and approximately 30 centimeters.23. A device, comprising a cast component derived from a metallic foilstack lamination mold, said component defining a feature having adimension of greater than 4 centimeters.
 24. A device, comprising a castcomponent derived from a metallic foil stack lamination mold.
 25. Thedevice of claim 24, said component comprising a mechanical component.26. The device of claim 24, said component comprising an electricalcomponent.
 27. The device of claim 24, said component comprising anelectronic component.
 28. The device of claim 24, said componentcomprising an optical component.
 29. The device of claim 24, saidcomponent comprising a fluidic component.
 30. The device of claim 24,said component comprising a biomedical component.
 31. The device ofclaim 24, said component comprising a biotechnological component.
 32. Asystem, comprising: a computed-tomography scanner comprising a castcomputed-tomography collimator descended from a lithographically-derivedmicro-machined metallic foil stack lamination mold.
 33. A system,comprising: a computed-tomography scanner comprising an x-ray sourcemounted to a circumference of a rotatable gantry, an array of x-raydetectors mounted to the circumference of the gantry, and a castcomputed-tomography collimator descended from a lithographically-derivedmicro-machined metallic foil stack lamination mold, said collimatormounted between said x-ray source and said x-ray detectors.
 34. Asystem, comprising: a nuclear medicine imaging camera comprising a castnuclear medicine collimator descended from a lithographically-derivedmicro-machined metallic foil stack lamination mold.
 35. A system,comprising: a nuclear medicine imaging camera comprising a scintillatorand a cast nuclear medicine collimator descended from alithographically-derived micro-machined metallic foil stack laminationmold, said collimator interposed between said scintillator and apredetermined position of a patient.
 36. A system, comprising: amammography X-ray imaging apparatus comprising a cast mammographyscatter reduction grid descended from a lithographically-derivedmicro-machined metallic foil stack lamination mold.
 37. A system,comprising: a mammography machine comprising a cast mammography scatterreduction grid descended from a lithographically-derived micro-machinedmetallic foil stack lamination mold, said grid disposed between anradiation source and a radiation detector.
 38. An imaging system,comprising a cast collimator descended from a lithographically-derivedmicro-machined metallic foil stack lamination mold.
 39. An imagingsystem, comprising a cast collimator descended from a micro-machinedmetallic foil stack lamination mold.
 40. An imaging system, comprising acast collimator descended from a metallic foil stack lamination mold.41. An image derived from a computed-tomography scanner comprising acast computed-tomography collimator descended from alithographically-derived micro-machined metallic foil stack laminationmold.
 42. An image derived from a nuclear medicine imaging cameracomprising a cast nuclear medicine collimator descended from alithographically-derived micro-machined metallic foil stack laminationmold.
 43. An image derived from a mammography machine comprising a castmammography scatter reduction grid descended from alithographically-derived micro-machined metallic foil stack laminationmold.
 44. An image derived from an imaging system comprising a castcollimator descended from a lithographically-derived micro-machinedmetallic foil stack lamination mold.
 45. An image derived from animaging system comprising a cast collimator descended from amicro-machined metallic foil stack lamination mold.
 46. An image derivedfrom an imaging system comprising a cast collimator descended from ametallic foil stack lamination mold.